Prasanna

HOTS Questions for Class 10 Science Chapter 4 Carbon and Its Compounds

Question 1.
An organic compound A of molecular formula C₂H₄ on reduction gives another compound B of molecular formula C₂H₆. B on reaction with chlorine in the presence of sunlight gives C of molecular formula C₂H₅Cl.
(a) Name the compounds A, B and C.
(b) Write chemical equation for the conversion of A to B and name the type of reaction.
Answer:
The compound A of molecular formula C₂H₄ is an alkene. Upon reduction with hydrogen, it gives ‘B’ of molecular formula C₂H₆. The compound ‘B’ upon chlorinadon gives ‘C’ of molecular formula C₂H₅Cl.

The reaction to called addition reaction.

More Resources

• HOTS Questions for Class 10 Science
• NCERT Solutions for Class 10 Science
• Value Based Questions in Science for Class 10
• NCERT Exemplar Solutions for Class 10 Science
• Previous Year Question Papers for CBSE Class 10 Science

Question 2.
Name the functional group of organic compounds that can be hydrogenated. With the help of suitable example, explain the process of hydrogenation mentioning the conditions of the reaction and any one change in physical property with the formation of the product. Name any one natural source of organic compounds that are hydrogenated.
Answer:
The functional group which can be easily hydrogenated is
The family is known as alkenes. The hydrogenation reaction can be carried by heating a member of the family (e.g. ethene) with hydrogen in the presence of a catalyst like nickel (Ni) For example.

Ethene is an unsaturated hydrocarbon while ethane is of saturated nature.
Edible oils such as coconut oil, olive oil, peanut oil etc. contain atleast one
in their molecules. These are regarded as unsaturated compounds. Upon hydrogenation, these get converted into fats which no longer contain any

Question 3.
An organic compound A’ of molecular formula C₂H₆O on oxidation with dilute alkaline KMnO₄ solution gives an acid ‘B’ with the same number of carbon atoms. Compound A’ is often used for sterilization of skin by doctors. Name the compound. Write the chemical equation involved in the formation of ‘B’ from A.
Answer:
The compound ‘B’ should contain a —COOH group as it is an acid. Since it has only two carbon atoms, the other carbon atom must represent CH₃ group. Thus, compound ‘B’ is ethanoic acid (CH₃COOH). The compound A used for the sterilization of skin by doctors is ethanol C₂H₅OH (C₂H₆O). The chemical reaction involved in the oxidation by dilute alkaline KMnO₄ solution also called Baeyers reagent is :

Question 4.
A to F are the structural formulae of some organic compounds :

(i) Give the letters which represent the same family.
(ii) Give the letters which do not represent hydrocarbons.
(iii) Flow can ‘C’ be converted into A ?
Answer:
(i) Letters ‘B’ and ‘D’ represent the family of alkynes.
(ii) Letters ‘E’ and ‘F’ donot represent any hydrocarbon.
(iii) ‘C’ can be converted into ‘A’ by passing hydrogen (H₂) in the presence of Ni at 473 K.

Question 5.
(a) A test tube contains a brown liquid in it. The colour of the liquid remains the same when methane is passed through it but it disappears when ethene is passed. Suggest the name of the liquid brown in colour. Give the chemical equation involved.
(b) The formula of an ester is C₃H₇COOC₂H₅. Write the formulae of the acid and alcohol from which the ester is prepared.
Answer:
(a) The brown liquid seems to be bromine dissolved in water. Methane (CH₄) is a saturated hydrocarbon and does not react with bromine. Ethene (C₂H₄) being unsaturated in nature, decolourises bromine and its colour therefore, disappears.

(b) In an ester, the left side in the molecular formula containing C₃H₇CO is derived from the acid while the right side having OC₂H₅ is from the alcohol. This means that the acid and alcohol participating in the ester are C₃H₇COOH and C₂H₅OH respectively. The formation of ester may be shown as follows :

Hope given HOTS Questions for Class 10 Science Chapter 4 Carbon and Its Compounds helpful to you. If you have any doubts, please comment below. We try to provide online math tutoring for you.

NCERT Exemplar Solutions for Class 10 Science Chapter 3 Metals and Non-metals

These Solutions are part of NCERT Exemplar Solutions for Class 10 Science. Here we have given NCERT Exemplar Solutions for Class 10 Science Chapter 3 Metals and Non-metals

NCERT Exemplar Solutions for Class 10 Science Chapter 3 Multiple Choice Questions

Question 1.
Which of the following properties is generally not shown by metals ?
(a) Electrical conduction
(b) Sonorous nature
(c) Dullness
(d) Ductility.
Answer:
(c). Metals have shining lustre and they mostly do not show any dullness.

More Resources

• NCERT Exemplar Solutions for Class 10 Science
• NCERT Solutions for Class 10 Science
• Value Based Questions in Science for Class 10
• HOTS Questions for Class 10 Science
• Previous Year Question Papers for CBSE Class 10 Science

Question 2.
The ability of metals to be drawn into thin sheets is known as
(a) ductility
(b) malleability
(c) sonorosity
(d) conductivity.
Answer:
(b).

Question 3.
Aluminium is used for making cooking utensils. Which of the following properties of the metal are responsible for the same ?
(i) Good thermal conductivity
(ii) Good electrical conductivity
(iii) Ductility
(iv) High melting point
(a) (i) and (ii)
(b) (i) and (iii)
(c) (ii) and (iii)
(d) (i) and (iv)
Answer:
(d). In order that a metal may be used for making cooking utensils, it must be good conductor of heat and also must have high melting point.

Question 4.
Which one of the following metals does not react with cold as well as hot water ?
(a) K
(b) Ca
(c) Mg
(d) Fe.
Answer:
(d).

Question 5.
Which of the following oxide(s) of iron would be obtained on prolonged reaction of iron with steam ?
(a) FeO
(b) Fe₂O₃
(c) Fe₃O₄
(d) Fe₂O₃ and Fe₃O₄
Answer:
(c).
3Fe (s) + 4H₂O (g) ———> Fe₃O₄ (s) + 4H₂ (g)

Question 6.
What happens when magnesium is treated with water ?
(i) It does not react with water
(ii) It reacts violently with water
(iii) It reacts less violently with water
(iv) Bubbles of hydrogen gas formed stick to the surface of the metal
(a) (i) and (iv)
(b) (ii) and (iii)
(c) (i) and (ii)
(d) (iii) and (iv)
Answer:
(d).
(iii) Magnesium reacts with water slowly to form magnesium hydroxide along with hydrogen gas
Mg(s) + 2H₂O(l) ———-> Mg(OH)₂(s) + H₂(g)
(iv) Bubbles of hydrogen gas stick to the surface of the metal.

Question 7.
Generally metals react with acids to give salt and hydrogen gas. Which of the following acids does not give hydrogen gas on reacting with metals (except Mn and Mg) ?
(a) H₂SO₄
(b) HCl
(c) HNO₃
(d) All of these.
Answer:
(c). HNO₃ is a strong oxidising agent. It oxidises metals to metal oxides and then to metal nitrates and itself is reduced to either nitric oxide (NO), nitruos oxide (N₂O) or nitrogen dioxide (NO₂). However, both Mg and Mn evolve hydrogen on reacting with the acid.

Question 8.
Composition of aqua-regia by volume is :
(a) Dil HCl (3) : Cone HNO₃ (1)
(b) Cone HCl (3) : Dil HNO₃ (1)
(c) Cone HCl (3) : Cone HNO₃ (1)
(d) Dil HC1 (3) : Dil HNO₃ (1)
Answer:
(c). is the correct answer.

Question 9.
Which of the following are not ionic compounds ?
(i) CaCl₂
(ii) HCl
(iii) CCl₄
(iv) NaCl
(a) (i) and (ii)
(b) (ii) and (iii)
(c) (iii) and (iv)
(d) (i) and (iii)
Answer:
(b). Both HCl and CCl₄ are covalent compounds in nature.

Question 10.
Which one of the following properties is not generally exhibited by ionic compounds ?
(a) Solubility in water
(b) Electrical conductivity in solid state
(c) High melting and boiling points
(d) Electrical conductivity in molten state.
Answer:
(b). Ionic compounds are conducting due to the movement of ions. Since the ions do not move in the solid state, these compounds are therefore, not conducting in the solid state.

Question 11.
Which of the following metals exist in their native state in nature ?
(i) Cu
(ii) Au
(iii) Zn
(iv) Ag
(a) (i) and (ii)
(b) (ii) and (iii)
(c) (ii) and (iv)
(d) (iii) and (iv)
Answer:
(c). Both Au and Ag are very little reactive. They exist in native state. However, the metal silver may also exist in some combined states (as minerals).

Question 12.
Metals are refined by using different methods. Which of the following metals are refined by electrolytic refining ?
(i) Ag
(ii) Cu
(iii) Na
(iv) Mg
(a) (i) and (ii)
(b) (i) and (iii)
(c) (ii) and (iii)
(d) (iii) and (iv)
Answer:
(a). Both Ag and Cu are very hard. These are called coinage metals and are purified by electrolytic refining.

Question 13.
Silver articles become black on prolonged exposure to air. This is due to the formation of
(a) AgCN
(b) Ag₂O
(c) Ag₂S
(d) Ag₂S and AgCN
Answer:
(c). Air contains traces of hydrogen sulphide (H₂S) gas which reacts with silver (Ag) to form Ag₂S black in colour.

Question 14.
Galvanisation is a method of protecting iron from rusting by coating with a thin layer of
(a) Chromium
(b) Copper
(c) Zinc
(d) Tin
Answer:
(c). Coating the surface of iron with zinc is called galvanization.

Question 15.
Stainless steel is a very useful material for our life. In stainless steel, iron is mixed with
(a) Ni and Cr
(b) Cu and Cr
(c) Ni and Cu
(d) Cu and Au.
Answer:
(a). is the correct answer.

Question 16.
If copper is kept open in air, it slowly loses its shining brown surface and gains a green coating. It is due to the formation of :
(a) CuSO₄
(b) CUCO₃CO(OH)₂
(c) CU(NO₃)₂
(d) CuO.
Answer:
(b). The green coating is due to the formation of basic copper carbonate which is CuCO₃.Cu(OH)₂.

Question 17.
Generally, metals are solid in nature. Which one of the following metals is found in liquid state at room temperature ?
(a) Na
(b) Fe
(c) Al
(d) Hg
Answer:
(d). Mercury (Hg) is a liquid at room temperature.

Question 18.
Which of the following metals are obtained by electrolysis of their chlorides in molten state ?
(i) Na
(ii) Ca
(iii) Fe
(iv) Cu
(a) (i) and (iv)
(b) (iii) and (iv)
(c) (i) and (iii)
(d) (i) and (ii)
Answer:
(d). Both Na and Ca are obtained by the electrolysis of their molten chlorides.

Question 19.
Generally non-metals are not lustrous. Which of the following non-metals is lustrous ?
(a) Sulphur
(b) Phosphorus
(c) Nitrogen
(d) Iodine.
Answer:
(d). Iodine is lustrous.

Question 20.
Which one of the following four metals would be displaced from the solution of its salts by other three metals ?
(a) Mg
(b) Cu
(c) Zn
(d) Fe
Answer:
(b). Cu is the least reactive and would be displaced from its salts by other metals.

Question 21.
5 mL each of concentrated HCl, HNO₃ and a mixture of concentrated HCl (15 mL) and concentrated HNO₃ (5 mL) were taken in test tubes labelled as A, B and C. A small piece of metal was put in each test tube. No change occurred in test tubes A and B but the metal got dissolved in test tube C. The metal could be
(a) Al
(b) Au
(c) Cu
(d) Ag
Answer:
(b). Gold (Au) dissolves in aqua regia.

Question 22.
An alloy is :
(a) an element
(b) a compound
(c) a homogeneous mixture
(d) a heterogeneous mixture
Answer:
(c). An alloy is a homogeneous mixture of two or more elements (metals or non-metals.)

Question 23.
An electrolytic cell consists of :
(i) positively charged cathode
(ii) negatively charged anode
(iii) positively charged anode
(iv) negatively charged cathode
(a) (i) and (ii)
(b) (iii) and (iv)
(c) (i) and (iii)
(d) (ii) and (iv)
Answer:
(b).

Question 24.
During electrolytic refining of copper, ir gets
(a) deposited on cathode
(b) deposited on anode
(c) deposited on cathode as well as anode
(d) remains in the solution.
Answer:
(a). Pure metal is always deposited on cathode.

Question 25.
An element ‘X’ is soft and can be cut with a knife. This is very reactive to air and cannot be kept in open air. It reacts vigorously with water. Identify the element from the following
(a) Mg
(b) Na
(c) S
(d) Mg
Answer:
(b). Sodium (Na) gives all the characteristics of the element X.

Question 26.
Alloys are homogeneous mixtures of a metal with a metal or non-metal. Which among the following alloys contain non-metal as one of its constituents ?
(a) Brass
(b) Gun metal
(c) Amalgam
(d) Steel.
Answer:
(d). Steel (stainless) contains very small percentage of carbon.

Question 27.
Which of the following statements is not correct for magnesium metal ?
(a) It burns in oxygen with dazzling flame
(b) It reacts with cold water to form magnesium oxide and evolves hydrogen gas
(c) It reacts with hot water to form magnesium hydroxide and evolves hydrogen gas
(d) It reacts with steam to form magnesium hydroxide and evolves hydrogen gas.
Answer:
(b). Magnesium (Mg) does not react with cold water since its position in the reactivity series of metals is not at the top.

Question 28.
Which among the following alloys contain mercury as one of its constituents ?
(a) Stainless steel
(b) German silver
(c) Solder
(d) Zinc amalgam.
Answer:
(d). All amalgams contain mercury as one of their constituents.

Question 29.
Reaction between the elements X and Y results in the compound Z. Whereas X loses electron, Y gains the same. Which of the following properties is not shown by Z ?
(a) Has high melting point
(b) Has low melting point
(c) Conducts electricity in molten state
(d) Occurs as solid
Answer:
(b). Z is an ionic compound. Therefore, it is not expected to have low melting point.

Question 30.
The electronic configurations of three elements X, Y and Z are X — 2, 8; Y — 2, 8, 6 and Z — 2, 8, 1. Which of the following is correct ?
(a) X is a metal
(b) Y is a metal
(c) Z is a non-metal
(d) Y is a non-metal and Z is a metal.
Answer:
(d). Y is sulphur (S) while Z is sodium (Na)

Question 31.
Although metals form basic oxides, which of the following metals form an amphoteric oxide ?
(a) Na
(b) Ca
(c) Zn
(d) Cu.
Answer:
(c). Zn forms amphoteric oxide ZnO which reacts with both the acids and the alkalies.

Question 32.
Generally, non-metals are not conductors of electricity. Which of the following is a good conductor of electricity ?
(a) Diamond
(b) Graphite
(c) Phosphorus
(d) Iodine
Answer:
(b). Graphite is a good conductor of electricity.

Question 33.
Electrical wires have a coating of an insulating material. The material, generally used is
(a) Lead
(b) Graphite
(c) PVC
(d) All can be used.
Answer:
(c). PVC (Poly Vinyl Chloride) coatings are generally used for insulating electrical wires.

Question 34.
Which of the following non-metals is a liquid ?
(a) Carbon
(b) Bromine
(c) Iodine
(d) Sulphur
Answer:
(b). Non-metal bromine is a liquid but in the molecular form (Br₂).

Question 35.
Which of the following can undergo a chemical reaction ?
(a) MgSO₄ + Zn
(b) ZnSO₄ + Fe
(c) CaSO₄ + Pb
(d) CuSO₄ + Al
Answer:
(d). Only Al can displace Cu from CuSO₄ solution since it is placed above Cu in the activity series.

Question 36.
Which one of the following figures correctly describes the process of electrolytic refining ?

Answer:
(c). Cu²⁺ ions are released from anode by the oxidation of copper (Cu). These migrate towards cathode and are reduced to copper (Cu).

NCERT Exemplar Solutions for Class 10 Science Chapter 3 Short Answer Questions

Question 37.
Iqbal treated a lustrous, divalent element M with sodium hydroxide. He observed the formation of bubbles in reaction mixture. He made the same observations when this element was treated with hydrochloric acid. Suggest how can he identify the produced gas. Write chemical equations for both the reactions.
Answer:
The divalent element M is a metal. It reacts with both sodium hydroxide (alkali) and dilute hydrochloric acid to evolve hydrogen gas

The gas burns with a pop sound when a burning match stick is brought near it.

Question 38.
During extraction of metals, electrolytic refining is used to obtain pure metals,
(a) Which material will be used as anode and cathode for refining of copper metal by this process
(b) Suggest a suitable electrolyte also,
(c) In this electrolytic cell, where do we get pure copper after passing electric current ?
Answer:
In the electrolytic refining of impure copper metal :
(a) A rod of impure copper is used as anode while that of pure copper as cathode.
(b) The electrolyte is a water soluble salt of copper. It is normally an aqueous solution of copper sulphate.
(c) On passing current, pure copper gets deposited at the cathode. It can be scrapped off later on. For more details.

Question 39.
Why should the metal sulphides and carbonates be converted to metal oxides in the process of extraction of metal from them ?
Answer:
It is quite easy to obtain a metal from metal oxide by carrying its reduction with a suitable reducing agent. However, metal sulphides and carbonates are converted to the oxide form and then reduced.

Question 40.
Generally, when metals are treated with mineral acids, hydrogen gas is liberated but when metals (except Mn and Mg), are treated with HNCfy, hydrogen is not liberated, why ?
Answer:
HNO₃ acts as a powerful oxidising agent along with acting as acid. In this case, hydrogen gas which is intially involved is oxidised to water.

Question 41.
Compound A’ and aluminium are used to join railway tracks,
(a) Identify the compound A’
(b) Name the reaction
(c) Write down its reaction with aluminium.
Answer:
Railway trakcs as we all know, are made up of iron. This means that the compound A is an oxide of iron (Fe₂CO₃). It is reduced by aluminium by thermit reaction with aluminium.

The reaction is highly exothermic and as a result, iron is in molten state and can weld the broken railway tracks. The process is also called aluminothermie reduction or thermit process.

Question 42.
When a metal ‘X’ is treated with cold water, it gives a basic salt ‘Y’ with molecular formula XOH (Molecular mass = 56) and liberates a gas ‘Z’ which easily catches fire. Identify X, Y and Z and also write the reaction involved.
Answer:
The atomic mass of metal X = 56 – Mass of OH group = 56 — 17 = 39u. This shows that the metal ‘X’ is potassium (K) and the basic salt ‘Y’ is potassium hydroxide (KOH). It is formed by reacting potassium with cold water. Hydrogen gas ‘Z’ evolved in the reaction catches fire.

Question 43.
A non-metal X-exists in two different forms Y and Z. Y is the hardest natural substance, whereas Z is a good conductor of electricity. Identify X, Y and Z.
Answer:
Since “Y” is the hardest occuring non-metal, it is diamond. The non-metal “X” is carbon. Y is the crystalline allotropie form of carbon. The other allotropie form Z which is a good conductor of electricity is graphite.

Question 44.
The following reaction takes place when aluminium powder is heated with Mn02.

(a) Is aluminium getting reduced ?
(b) Is Mn02 getting oxidised ?
Answer:
(a) Aluminium is getting oxidised to Al₂O₃.
(b) Manganese dioxide is getting reduced to Mn.

Question 45.
What are the constituents of solder alloy ? Which property of solder makes it suitable for welding electrical wires ?
Answer:
The constituents of solder alloy are ; lead (Pb) and tin (Sn). Being a low melting solid and also a good conductor of electricity, solder is used for welding electrical wires and cables.

Question 46.
A metal ‘M’, which is used in thermite process, when heated with oxygen gives an oxide, which is amphoteric in nature. Identify ‘M’ and its oxide. Write down the reactions of oxide with HCl and NaOH.
Answer:
The information suggests that the metal ‘M’ is aluminium (Al). The formula of its oxide is Al₂O₃ which is amphoteric in nature. It reacts with both acid and base.

Question 47.
A metal that exists as a liquid at room temperature is obtained by heating its sulphide in the presence of air. Identify the metal and its ore and give the reaction involved.
Answer:
Mercury is the metal which exists as a liquid at room temper nature. It can be obtained by heating the sulphide ore in the presence of air. The process is known as roasting. The chemical reactions involved are :

Question 48.
Give the formulae of the stable binary compounds that would be formed by the combination of following pairs of elements.
(a) Ca and N₂
(b) Li and O₂
(c) Ca and Cl₂
(d) K and
Answer:
(a) Calcium nitride (Ca₃N₂)
(b) Lithium oxide (Li₂O)
(c) Calcium chloride (CaCl₂)
(d) Potassium oxide (K₂O).

Question 49.
What happens when
(a) ZnCO₃ is heated in the absence of oxygen ?
(b) a mixture of Cu₂O and Cu₂S is heated ?
Answer:
(a) A mixture of ZnO(s) and CO₂ is formed

(b) A mixture of copper and SO₂ is formed.

Question 50.
A non-metal A is an important constituent of our food and forms two oxides B and C. Oxide B is toxic whereas C causes global warming
(a) Identify A, B and C
(b) To which Group of Periodic Table does A belong ?
Answer:
The non-metal A is carbon. It is an important constituent of our food in different forms. For example, glucose (C₆H₁₂O₆) contains carbon. In fact, all food materials are organic compounds and these contain carbon as essential constituent. The two oxides of carbon are, carbon monoxide (B) and carbon dioxide (C). Carbon dioxide causes global warming.
(a) A = Carbon (C) ;
B = Carbon monoxide (CO) ;
C = Carbon dioxide (CO₂)
(b) Carbon is the first member of group 14 in the Long form of Periodic Table.

Question 51.
Give two examples each of the metals that are good conductors and poor conductors of heat respectively.
Answer:
Good conductors of heat : Ag and Cu Poor conductors of heat : Pb and Hg.

Question 52.
Name one metal and one non-metal that exist in liquid state at room temperature. Also name two metals having melting point less than 310 K (37°C).
Answer:
The metal mercury (Hg) and non-metal (Br₂) exist in liquid state at room temperature.
The two metals with melting points less than 310 K are ; cesium (Cs) with melting point 301 K and gallium (Ga) with melting point 303 K.

Question 53.
An element ‘A’ reacts with water to form a compound ‘B’ which is used in white washing. The compound ‘B’ on heating forms an oxide ‘C’ which on treatment with water gives back ‘B’. Identify ‘A’, ‘B’ and ‘C’ and give the reactions involved.
Answer:
Since the compound ‘B’ is used for white wash, it is calcium hydroxide and the element ‘A’ is calcium. Upon heating ‘B’ forms calcium oxide ‘C’. It reacts with water to give calcium hydroxide ‘B’ again.

Question 54.
An alkali metal A gives a compound B (molecular mass = 56) on reacting with water. The compound ‘B’ gives a soluble compound ‘C’ on treatment with aluminium oxide. Identify A, B and C and give the reaction involved.
Answer:
As explained under Question 42, the alkali metal A is potassium (K) and on reacting with water, it forms a compound ‘B’ which is potassium hydroxide. This upon reacting with aluminium oxide (Al₂O₃) forms potassium metaluminate ‘C’.

Question 55.
Give the reaction involved during extraction of zinc from its ore by
(a) roasting of zinc ore
(b) calcination of zinc ore
Answer:

Question 56.
A metal M does not liberate hydrogen from acids but reacts with oxygen to give a black coloured product. Identify M and black coloured product and also explain the reaction of M with oxygen.
Answer:
The avilable information suggests that the metal M is copper (Cu). It does not liberate hydrogen since it is placed below hydrogen in the reactivity series. Copper reacts with oxygen upon heating to form cupric oxide (CuO) which is black in colour.

Question 57.
An element forms an oxide A₂O₃ which is acidic in nature. Identify A as a metal or non-metal.
Answer:
Since the oxide A₂O₃ is acidic in nature, the element A is non-metal.

Question 58.
A solution of CuSO₄ was kept in an iron pot. After few days, the iron pot was found to have a number of holes in it. Explain the reason in terms of reactivity. Write the equation of the reaction involved.
Answer:
Iron (Fe) is placed above copper (Cu) in the reactivity series. This means that a chemical reaction had occurred between iron (iron pot) and aqueous CuSO₄ solution.

Since iron was consumed in the reaction, a number of holes appeared in the pot.

NCERT Exemplar Solutions for Class 10 Science Chapter 3 Long Answer Questions

Question 59.
A non-metal A which is the largest constituent of air, when heated with H₂ in 1 : 3 ratio in the presence of catalyst (Fe) gives a gas B. On heating with O₂ it gives an oxide C. If this oxide is passed into water in the presence of air, it gives an acid D which acts as a strong oxidising agent.
(a) Identify A, B, C and D.
(b) To which group of periodic table does this non-metal belong ?
Answer:
(a) The available information suggests that the non-metal A is nitrogen (N) and its molecular form is N₂. It is the major constituent of air (about 79 per cent by volume). It reacts with H₂ upon heating m the presence of iron catalyst (Fe) to form ammonia (NH₃) gas(g)

Upon heating with oxygen, nitrogen forms intially nitric oxide (NO) and then nitrogen dioxide (C). The latter reacts with water in the presence of oxygen to form nitric acid (D). The acid acts as strong oxidising agent.

(b) The element nitrogen is the first member of group 15 of Modern periodic table.

Question 60.
Give the steps involved in the extraction of metals of low and medium reactivity from their respective sulphide ores.
Answer:
Extraction of Metals present low in the Activity series
Silver (Ag), gold (Au) and platinum (Pt) generally occur in the free or native state. This means that they can be isolated rather easily. Metals like copper (Cu) and mercury (Hg) are comparitively more reactive and occur in combined states. For example, the ore of mercury is cinnabar (HgS) while that of copper is copper glance (Cu₂S). Both are converted into metallic form upon heating in air or oxygen.

Extraction of Metals present in the middle of the Activity series
The metals present in the middle of the series are zinc, iron, chromium, nickel, cobalt, lead etc. These are usually present as sulphides or carbonares in nature. However, it is quite easy to obtain a metal from its oxide form which is then reduced to the metallic state. The various steps involved in the process of extraction are briefly discussed.
(a) Calcination :
Calcination may be defined as the process of heating the ore below its melting point in the absence of air.
As a result of calcination, the following changes take place

• Moisture is driven out and the ore becomes dry.
  
• Some hydrated ores decompose and become anhydrous by losing molecules of water of crystallisation. For example, heat
  

(b) Roasting :
Roasting may be defined as the process of heating the ore below its melting point with excess of air.
As a result of roasting, the following changes occur :

• Any organic matter if present, gets destroyed.
• Impurities of non-metals such as sulphur, arsenic or phosphorus are converted into their volatile oxides which are removed. For example,
  

• Sulphides of the metals are converted into their oxides. For example,
  
• Small amounts of sulphides may also be converted into sulphates as a^s result of roasting. For example,

Question 61.
Explain the following
(a) Reactivity of Al decreases if it is dipped in cone. HNO₃
(b) Carbon cannot reduce the oxides of Na or Mg.
(c) NaCl is not a conductor of electricity in solid state whereas it does conduct electricity in aqueous solution as in molten state
(d) Iron articles are galvanised.
(e) Metals like Na, K, Ca and Mg are never found in their free state in nature.
Answer:
(a) When Al metal is dipped in cone. HNO₃ for sometime, it is oxidised initially to aluminium oxide (Al₂O₃). The oxide gets deposited on the surface of the metal and forms a protective coating an the surface. The metal is said to become passive towards air, acids and alkalies. Its reactivity therefore, decreases.
(b) Both Na and Mg are more reactive than carbon. Therefore, carbon is not in a position to reduce the oxides of these metals.
(c) NaCl is an ionic compound. Its electrical conductivity is due to the mobility of Na⁺ and Cl^– ions. These ions cannot move in the solid state. However, they can do so either in molten state of the salt or when it forms and aqueous solution in water.
(d) Iron has a tendency to get rusted in atmosphere by reacting with oxygen and water vapours present in air. In order to check rusting, iron articles are generally coated with zinc. This process is known as galvanization.
(e) All these metals are placed high in reactivity series of metals. They are quite reactive and do not exist in free states.

Question 62.
(i) Given below are the steps lor extraction of copper from its ore. Write the reaction involved.
(a) Roasting of copper (1) sulphide
(b) Reduction of copper (1) oxide with copper (1) sulphide.
(c) Electrolytic refining
(ii) Draw a neat and well labelled diagram for electrolytic refining of copper.
Answer:

This reaction in which one of the reactants (Cu₂S) carries the reduction of the product (Cu₂O) is known as auto-reduction.
(c) Reactions taking place in electrorefensing are :

(ii) For the diagram of electro-refining,

Question 63.
Of the three metals X, Y and Z, X reacts with cold water, Y with hot water and Z with steam only. Identify X, Y and Z and also arrange them in order of increasing reactivity.
Answer:
The answer is based on the relative positions of the metals in the reactivity series. The reactivity with water decreases down the series.

• Metal X is Na or K
• Metal Y is Mg or Ca
• Metal Z is Al or Fe.

Order of increasing reactivity : Z < Y < X.

Question 64.
Two ores ‘X’ and ‘Y’ were taken. On heating, ore ‘X’ gives CO₂ whereas ore ‘Y’ gives SO₂. What steps will you take to convert them into respective metals ?
Answer:
Since the ore ‘A’ of the metal gives CO₂ upon heating, it is some metal carbonate (MCO₃). It can be converted to the metallic form as follows :

Since the ore ‘Y’ of the metal gives SO₂ upon heating, it can be some metal sulphide (MS). It can be converted to the metallic form as follows :

Hope given NCERT Exemplar Solutions for Class 10 Science Chapter 3 Metals and Non-metals are helpful to complete your science homework.

If you have any doubts, please comment below. Learn Insta try to provide online science tutoring for you.

Value Based Questions in Science for Class 10 Chapter 3 Metals and Non-metals

These Solutions are part of Value Based Questions in Science for Class 10. Here we have given Value Based Questions in Science for Class 10 Chapter 3 Metals and Non-metals

Question 1.
A customer approached a newly trained Goldsmith and asked him to make some ornaments. For this he gave advance money also. The Goldsmith bought a bar of 24-carat gold from the market and tried to make ornaments from it. He was not successful because the gold was too soft to handle. He approached a trained Goldsmith who asked him to use 22-carat gold for this purpose. He was now quite successful and could make the ornaments ?

1. What is the difference between 24-carat gold and 22-carat gold ?
2. What was wrong with 24-carat gold ?
3. How did trained Goldsmith help the freshly trained Goldsmith ?
4. What is the value associated with this episode ?

Answer:

1. 24-carat gold is pure gold while 22-carat gold is comparatively less pure.
2. Pure or 24-carat gold is very soft, little malleable and ductile. It is quite difficult to work on it. But 22 carat gold (alloy) is comparatively hard, more malleable and ductile
3. Freshly trained Goldsmith realised his mistake and could complete the order. Otherwise he might have been in problem.
4. The trained Goldsmith had a big heart and did not bother about the professional jealousy. He was very sincere in his approach and helped the junior colleage.

More Resources

• Value Based Questions in Science for Class 10
• HOTS Questions for Class 10 Science
• NCERT Solutions for Class 10 Science
• NCERT Exemplar Solutions for Class 10 Science
• Previous Year Question Papers for CBSE Class 10 Science

Question 2.
A student was asked to purify a sample of copper extracted by a suitable method. He constructed a-cell in which a rod of impure copper was made cathode while that of pure copper as anode. The electrolyte was aqueous CuSO₄ solution. On passing electric current nothing happened. He realised his mistake and connected the electrodes in the reverse order. He was now quite successful in his mission.

1. What was his mistake ?
2. How did he rectify it ?
3. Write a chemical equation for the reaction.

Answer:

1. Impure copper cannot be made cathode and pure copper as the anode.
2. He changed over. Pure copper was made cathode while impure copper as the anode.
3. The chemical equations for the process are :
   

Hope given Value Based Questions in Science for Class 10 Chapter 3 Metals and Non-metals are helpful to complete your science homework.

If you have any doubts, please comment below. Learn Insta try to provide online science tutoring for you.

HOTS Questions for Class 10 Science Chapter 3 Metals and Non-metals

These Solutions are part of HOTS Questions for Class 10 Science. Here we have given HOTS Questions for Class 10 Science Chapter 3 Metals and Non-metals

Question 1.
A student has been collecting silver coins and copper coins. One day she observed a black coating on silver coins and a green coating on copper coins. Which chemical phenomenon is responsible for these coatings ? Write the chemical names of black and green coatings ?
Answer:
The phenomenon is known as corrosion. Air contains traces of hydrogen sulphide gas which reacts with silver metal present in the coin to form silver sulphide. It is black in colour.

Similarly, copper present in the coin reacts with oxygen and traces of both carbon dioxide and water vapours present in air to form a green mass. It is chemically basic copper carbonate :

More Resources

• HOTS Questions for Class 10 Science
• NCERT Solutions for Class 10 Science
• Value Based Questions in Science for Class 10
• NCERT Exemplar Solutions for Class 10 Science
• Previous Year Question Papers for CBSE Class 10 Science

Question 2.
You are provided with three metals : Sodium, magnesium and copper. Using only water as the reactant, how will you identify them ?
Answer:
The metal which reacts violently with cold water and catches fire is sodium.

1. The metal which evolves hydrogen gas upon heating with water is magnesium.
2. The metal which does not react with water even on strong heating is copper.

Question 3.
E is an element amongst copper, zinc, aluminium and iron. It shows following properties :
(a) One of its ores is rich in E₂O₃
(b) E₂O₃ is not attacked by water,
(c) It forms two chlorides ECl₂ and ECl₃. Name the element and justify your answer.
Answer:
The clue for the correct answer is the formation of ECl₂ and ECl₃. This shows that the element E has variable valencies of 2 and 3. Out of the elements listed, only iron exists in divalent and trivalent forms.
(a) The ore rich in Fe₂O₃ is haematite.
(b) Haematite (Fe₂O₃) is not attacked by water.
(c) The two chlorides are : iron (II) chloride or FeCl₂ and iron (III) chloride or FeCl₃.

Question 4.
An element reacts with oxygen to form an oxide which dissolves in dilute hydrochloric acid. The oxide formed also turns a solution of red litmus blue. Is the element a metal or non-metal ? Explain with the help of a suitable example.
Answer:
The oxide of the element is basic as it turns red litmus solution blue. This means that the element is a metal (M). Let the metal be sodium (Na). The chemical equations that are involved are given as follows :

Question 5.
An element E combines with oxygen to form an oxide E₂O which is a good conductor of electricity.
Give the following information:

1. How many electrons will be present in the valence shell of the element E ?
2. Write the formula of the compound formed when the element E combines with chlorine.

Answer:

1. From the formula E₂O of the oxide, it is clear that the valency of the element E is one. This means that it has only one electron in the valence shell.
2. We know that chlorine is monovalent. Sine the valency of the element E is a also one, the formula of the chloride of the element is ECl.

Question 6.
An element A’ catches fire in water and burns with golden yellow flame in air. It reacts with another element ‘B’, present in group 17 to give a product ‘C’. An aqueous solution of product ‘C’ on electrolysis gives a compound ‘D’ and liberates hydrogen. Identify A, B, C and D.
Answer:
Since the element A’ catches fire in water and burns with golden yellow flame, it is sodium (Na). The element ‘B’ with atomic number 17 is chlorine (Cl). Both these combine to form sodium chloride (NaCl) which is designated as ‘C’. Upon electrolysis, sodium chloride gives sodium hydroxide (D) and evolves hydrogen along with chlorine.

Hope given HOTS Questions for Class 10 Science Chapter 3 Metals and Non-metals are helpful to complete your science homework.

If you have any doubts, please comment below. Learn Insta try to provide online science tutoring for you.