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

These NCERT Solutions for Class 10 Science Chapter 3 Metals and Non-Metals Questions and Answers are prepared by our highly skilled subject experts to help students while preparing for their exams.

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

Class 10 Science Chapter 3 Metals and Non-Metals InText Questions and Answers

In-text Questions (Page 40)

Question 1.
Give an example of a metal which
(i) is a liquid at room temperature.
(ii) can be easily cut with a knife.
(iii) is the best conductor of heat.
(iv) is a poor conductor of heat.
Answer:
(i) Mercury,
(ii) Sodium,
(iii) Silver,
(iv) Lead.

Question 2.
Explain the meanings of malleable and ductile.
Answer:
Metals are malleable i.e., they can be hammered into sheets because layer of atoms slide over each other. Gold and silver and most malleable while copper and aluminium are also highly malleable. Metals such as aluminium can be rolled into thin sheets, because the regular layers of atoms can slide over one another.

Metals have ductile nature i.e., they can be drawn into wires. The abiltiy of metals to be drawn into thin wires is called ductility. Gold and silver are the most malleable metals, A wire of about 2 km length can be drawn from one gram of gold.

In-text Questions (Page 46)

Question 1.
Why is sodium kept in kerosene oil?
Answer:
Sodium is highly reactive metal and it combines with oxygen of air and water (moisture) to form oxides and hydroxide vigorously.
NCERT Solutions for Class 10 Science Chapter 3 Metals and Non-Metals 1
In order to store these metals these are kept in kerosene oil.

Question 2.
Write equations for the reactions of
(i) Iron with steam
(ii) Calcium and potassium with water
Answer:
NCERT Solutions for Class 10 Science Chapter 3 Metals and Non-Metals 2

Question 3.
Samples of four metals A, B, C and D were taken and added to the following solution one by one. The results obtained have been tabulated as follows:
NCERT Solutions for Class 10 Science Chapter 3 Metals and Non-Metals 3
Use the table above to answer the following questions about metals A. B, C and D.
(i) Which is the most reactive metal?
(ii) What would you observe if B is added to a solution of copper (II) sulphate?
(iii) Arrange the metals A, B, C and D in the order of decreasing reactivity?
Answer:
(i) ‘B’ is the most reactive metal.
(ii) ‘B’ displaces copper from copper sulphate.
(iii) Order of decreasing reactivity of metal A, B, C and D.
B > A > C > D

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

Question 4.
Which gas is produced when dilute hydrochloric acid is added to a reactive metal?
Write the chemical reaction when iron reacts dilute H2SO4.
Answer:
Hydrogen gas is produced when dilute hydrochloric acid is added to a metal.
NCERT Solutions for Class 10 Science Chapter 3 Metals and Non-Metals 4

Question 5.
What would you observe when zinc is added to a solution o iron (II) sulphate ? Write the chemical reaction that takes place.
Answer:
FeSO4(aq) + Zn(s) → ZnSO4(aq) + Fe(s)
Iron (Il) sulphate solutIon has greenish colour. A more reactive metal can displace a less reactive metal from its salt solution. Zinc is more reactive than iron so it displaces iron from iron sulphate solution and the greenish colour of solution changes into colourless because zinc sulphate solution is colourless.

In-text Questions (Page 49)

Question 1.
(i) Write the electron dot structures for sodium oxygen and magnesium.
(ii) Show the formation of Na2O and MgO by the transfer of electrons.
(iii) What are the ions present in these compounds ?
Answer:
NCERT Solutions for Class 10 Science Chapter 3 Metals and Non-Metals 5
NCERT Solutions for Class 10 Science Chapter 3 Metals and Non-Metals 6

Question 2.
Why do ionic compounds have high melting point ?
Answer:
Ionic compounds have high melting point because ions are tightly held together by strong electrostatic forces of attraction and to break this strong interionic attraction a large amount of energy is needed.

In-text Questions (Page 53)

Question 1.
Define the terms :
(i) mineral (ii) ore and (iii) gangue
Answer:
(i) Mineral: In combined state metals are found in the earth crust as oxides, carbonates, sulphides, silicates, phosphates etc. These compounds are known as minerals. All the ores are minerals but all the minerals are not ores.
(ii) Ore : The mineral from which the metal can be economically and conveniently extracted is called ore. For example, bauxite is the ore of aluminium.
(iii) Gangue : The eartly, rocky and silicious impurities associated with the minerals are collectively known as gangue or matrix.

Question 2.
Name two metals which are found in nature in the free state.
Answer:
Gold, Silver.

Question 3.
What chemical process is used for obtaining a metal from its oxide ?
Answer:
Reduction Process.

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

In-text Questions (Page 55)

Question 1.
Metallic oxides of zinc, magnesium and copper were heated with the following metals:
NCERT Solutions for Class 10 Science Chapter 3 Metals and Non-Metals 7
In which cases will you find displacement reactions taking place?
Answer:
Magnesium is more reactive than zine and copper so it can displace zinc from zinc oxide and copper from copper oxide.
NCERT Solutions for Class 10 Science Chapter 3 Metals and Non-Metals 8
Zinc is more reactive than copper so it can displace copper from copper oxide.
\(\mathrm{CuO}+\mathrm{Zn} \stackrel{\text { Heat }}{\longrightarrow} \mathrm{ZnO}+\mathrm{Cu}\)

So when ZnO and CuO react with Mg and CuO reacts with ‘Zn’ they gives displacement reactions.
NCERT Solutions for Class 10 Science Chapter 3 Metals and Non-Metals 9

Question 2.
Which metals do not corrode easily?
Answer:
Least reactive metals such Au (Gold), PL (Platinum), Ag (Silver).

Question 3.
What are alloys?
Answer:
An alloy is a homogenous mixture of two as more metals or a metal with a non-metal. E.g. Brass, Bronze etc.

Class 10 Science Chapter 3 Metals and Non-Metals Textbook Questions and Answers

Page No. 56, 57

Question 1.
Which of the following pairs will give displacement reactions:
(a) NaCl solution and copper metal
(b) MgCl2 solution and aluminium metal
(c) FeSO4 solution and silver metal
(d) AgNO3 solution and copper metal
Answer:
(d) AgNO3 solution and copper metal.

Question 2.
Which of the following methods is suitable for preventing an iron frying pan from rusting.
(a) applying grease
(b) applying paint
(c) applying a coating of zinc
(d) all of the above
Answer:
(d) All of the above

Question 3.
An element reacts with oxygen to give a compound with a high melting point. This compound is also soluble in water. The element is likely to be:
(a) calcium
(b) carbon
(c) silicon
(d) iron
Answer:
(d) Calcium.

Question 4.
Food cans are coated with tin and not with zinc because:
(a) zinc is costlier than tin
(b) zinc has a higher melting point than tin
(c) zinc is more reactive than tin
(d) zinc is less reactive than tin
Answer:
(a) Zinc is costlier than tin

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

Question 5.
You are given a hammer, a battery, a bulb, wires and a switch.
(a) How could you use them to distinguish between metals and non metals?
(b) Assess the usefulness of these tests in distinguishing between metals and non-metals.
Answer:
(a) A hammer can be used to check the malleability of metals. Metals are malleable i.e., they can be hammered into sheets because layer of atoms slide over each other. But a non-metal cannot be hammered into sheets. However non-metals are brittle in nature. When a metal is connected with a battery and a bulb through wires, bulb does not glow.

(b) Metals are malleable but non-metals are brittle. Malleability is an important property of metals. Metals can be distinguished by using hammer.

Metals are good conductors of electricity but non-metals are bad conductors of electricity. So conductivity method can also be used to distinguish between metals and non-metals. Except graphite all non-metals are bad conductors of electricity.

Question 6.
What are amphoteric oxides? Give two examples of amphoteric oxides.
Answer:
Amphoteric oxide: A metal oxide which shows both acidic as well as basic character i.e., such metal oxides react with both acids as well as bases to produce salts and water is known as amphoteric oxides.

For examples Aluminum oxide (Al2O3) and Zinc oxide (ZnO).

Question 7.
Name two metals which will displace hydrogen from dilute acids, and two metals which will not.
Answer:
Metals which will displace hydrogen from dilute acids : Zn, Mg.
Metals which will not displace hydrogen from dilute acids: Cu, Ag.

Question 8.
In the electrolytic refining of a metal M, what would you take as the anode, the cathode and the electrolyte.
Answer:
In the electrolyte refining of a metal ‘M’, the crude metal is made anode whereas the thin sheet of pure metal ‘M’ is made cathode. Electrolyte is the solution of some salt of the metal ‘M’.

Question 9.
Pratyush took Sulphur power on a spatula and heated it. He collected a gas evolved by inverting a test tube over it as shown in figure:
NCERT Solutions for Class 10 Science Chapter 3 Metals and Non-Metals 10
(a) What will be the action of gas on
(i) dry litmus paper?
(ii) moist litmus paper?
(b) Write a balanced chemical equation for the reaction taking place.
Answer:
(a) (i) No effect on dry litmus paper.
(ii) It turns the colour of moist blue litmus paper into red because the evolved gas has acidic nature.
NCERT Solutions for Class 10 Science Chapter 3 Metals and Non-Metals 11
Sulphurous acid turns blue litmus to red.

Question 10.
State two ways to prevent the rusting of iron.
Answer:
The rusting of iron can be prevented by painting, oiling, greasing, galvanishing, chromeplating, anodising or making alloys.
1. Barrier Protection : In barrier protection, a protective film is introduced between iron and atmospheric oxygen and water. Barrier protection can be achieved by any of the following methods:

  • By painting the surface
  • By coating the surface with a thin film of oil or grease.
  • By electroplating iron with some non-conosive metal such as nickel, copper etc.

2. Galvanisation: Zinc metal is generally used for protecting iron and the process is called galvanisation. Galvanised iron sheets maintain their shine due to the formation of a protective layer of basic zinc carbonate due to the reaction between zinc, oxygen, carbon dioxide and moisture in air.

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

Question 11.
Give reasons:
(a) Platinum, gold and silver are used to make jewellery.
(b) Sodium, potassium and lithium are stored under oil.
(c) Aluminium is a highly reactive metal, yet it is used to make utensils for cooking
(d) Carbonate and sulphides ores are usually converted into oxides during the process of extraction.
Answer:
(a) Platinum, gold and silver have high metallic lustre and are less reactive metals. So these metals are not corroded when exposed to air and moisture. That is why these metals are used to make jewellery.

(b) Sodium, potassium and lithium are highly reactive metals. When these metals are exposed to atmosphere, they react with oxygen, moisture and carbon dioxide present in the air forming Oxides, hydroxides and carbonates. In order to prevent the reaction, the alkali metals i.e., sodium, potassium and lithium are stored under oil.

(c) Aluminium is a highly reactive metal. It readily reacts with oxygen of air to form oxide and once a thin layer of oxides formed on surface then it protect the metal from further action and simultaneously it a good conductor of heat.
NCERT Solutions for Class 10 Science Chapter 3 Metals and Non-Metals 12
Due to these reasons aluminium is used to make utensils for cooking

(d) The metals in the middle of the activity series such as iron, zinc, lead, copper etc., are moderately reactive. These metals are usually present as Sulphides or carbonates in nature. It is easier to obtain a metal from its oxide, as compared to its sulphides and carbonates. So, prior to reduction, the metal sulphides and carbonates must be converted into metal oxides.

Question 12.
You must have seen tarnished copper vessels being cleaned with lemon or tamarind juice. Explain why these sour substances are effective in cleaning the vessels.
Answer:
Copper reacts with moist carbondioxide in the air and slowly loses its shiny brown surface and gains a green coat. This green substance is copper carbonate (CuCO3). Sour substances like lemon or tamarind juice contains acids such as Citric acid or methanoic and copper carbonate is basic in nature so it reacts with acids to form water soluble salts and thus copper vessels can be cleaned.

Question 13.
Differentiate between metal and non-metal on the basis of their chemical properties.
Answer:
NCERT Solutions for Class 10 Science Chapter 3 Metals and Non-Metals 13

Question 14.
A man went door to door posing as a goldsmith. He promised to bring back the glitter of old and dull gold ornaments, an unsuspecting lady gave a set of gold bangles to him which he dipped in a particular solution. The bangles sparkled like new but their weight was reduced drastically. The lady was upset but after a futile argument the man beat a hasty retreat. Can you play the detective to find out the nature of the solution he had used?
Answer:
Gold is a least reactive metal. It does react with oxygen, Carbondioxide, water, even cone. Acids. But it is dissolved in aqua regia. Aqua regia (Latin name for “royal water”) is a freshly prepared mixture of concentrated hydrocloric acid and concentrated nitric acid in the ratio of 3: 1. It is one of the few reagents that is able to dissolve gold and platinum. So the solution used by the man is aqua regia.

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

Question 15.
Give the reason why copper is used to make hot water tanks but steel (an alloy of iron) is not.
Answer:
Metals at the top of the reactivity series are most reactive and are not available in nature in free state and all metals placed above hydrogen can displace hydrogen from their compounds such as water and acids.

According to reactivity series iron is more reactive than copper when iron is exposed to hot water it corroded vigorously but copper is not. That is why copper is used to make hot water tanks but steel (an alloy of iron) is not.
NCERT Solutions for Class 10 Science Chapter 3 Metals and Non-Metals 14

Class 10 Science Chapter 3 Metals and Non-Metals Textbook Activities

Activity 3.1 (Page 37)

  • Take samples of iron, copper, aluminium and magnesium. Note the appearance of each sample.
  • Clean the surface of each sample by rubbing them with sand paper and note their appearance again.

Observation: Metals, in their pure state, have a shining surface. This property is called metallic lustre,

Activity 3.2 (Page 37)

  • Take small pieces of iron, copper, aluminium, and magnesium. Try to cut these metals with a sharp knife and note your observations.
  • Hold a piece of sodium metal with a pair of tongs.

CAUTION: Always handle sodium metal with care. Dry it by pressing between the folds of a filter paper.

  • Put it on a watch-glass and try to cut it with a knife.

Question 1.
What do you observe?
Answer:
Observation: Metals are generally hard, but sodium is a soft metal. We observe that sodium metal cuts with the help of knife.

Activity 3.3 (Page 38)

  • Take pieces of iron, zinc, lead and copper.
  • Place any one metal on a block of iron and strike it four or five times with a hammer. What do you observe?
  • Repeat with other metals.
  • Record the change in the shape of these metals.

Observations: We find that some metals (Iron, Zinc, Copper) can be beaten into thin sheets. This property of metals is called malleability. Gold and silver are the most malleable metals?

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

Activity 3.4 (Page 38)

  • Consider some metals such as iron, copper, aluminium, lead etc.
  • Which is the above metals are also available in the form of wires ?

Observation : Iron, Copper and Aluminium metals are available in the form of wires. The ability of metals to be drawn into thin wires is called ductility. Gold is the most ductile metal.

Activity 3.5 (Page 38)

  • Take an aluminium or copper wire. Clamp this wire on a stand, as shown in Fig.
  • Fix a pin to the free end of the wire using wax.
  • Heat the wire with a spirit lamp, candle or a burner near the place where it is clamped.
  • What do you observe after some time?

NCERT Solutions for Class 10 Science Chapter 3 Metals and Non-Metals 15

  • Note your observations. Does the metal wire melt?

Observation : Metal wire does not melt but the wax is melted and the pin fall down on the earth. This activity shows that metals are good conductors of heat and have high melting point.

Activity 3.6 (Page 39)

  • Set up an electric circuit as shown in Fig.
    NCERT Solutions for Class 10 Science Chapter 3 Metals and Non-Metals 16
  • Place the metal to.be tested in the circuit between terminals A and B as shown.
  • Does the bulb glow? What does this indicate?

Observation : Yest the bulb glows. This indicates that metals are good conductors of electricity.

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

Activity 3.7 (Page 39)

  • Collect samples of carbon (coal or graphite), sulphur and iodine.
  • Carry out the Activities 3.1 to 3.6 with these non-metals and record your observations.

Compile your observations regarding metals and non-metals in Table 3.1.
NCERT Solutions for Class 10 Science Chapter 3 Metals and Non-Metals 17

Activity 3.8 (Page 40)

  • Take a magnesium ribbon and some sulphur powder.
  • Bum the magnesium ribbon. Collect the ashes formed and dissolve them in water.
  • Test the resultant solution with both red and blue litmus paper.
  • Is the product formed on burning magnesium acidic or basic?
  • Now burn sulphur powder. Place a test tube over the burning sulphur to collect the fumes produced.
  • Add some water to the above test tube and shake.
  • Test this solution with blue and red litmus paper.
  • Is the product formed on burning sulphur acidic or basic?
  • Can you write equations for these reactions?

Observation: The product formed on burning of magnesium is basic in nature because it turns red litmus to blue.
The produt formed on burning of sulphur is acidic in nature because it turns blue litmus to red
NCERT Solutions for Class 10 Science Chapter 3 Metals and Non-Metals 18
Magnesium hydroxide is basis in nature.
NCERT Solutions for Class 10 Science Chapter 3 Metals and Non-Metals 19
Sulphurous acid is acidie in nature.

Activity 3.9 (Page 41)

CAUTION : The following activity needs the teacher’s assistance. It would be better if students wear eye protection.

  • Hold any of the samples taken above with a pair of tongs and try burning over a; flame. Repeat with the other metal samples.
  • Collect the product if formed.
  • Let the products and the metal surface cool down.
  • Which metals burn easily?
  • What flame colour did you observe when the metal burnt?
  • How does the metal surface appear after burning?
  • Arrange the metals in the decreasing order of their reactivity towards oxygen.
  • Are the products soluble in water?

Observation: Let us take sodium, magnesium calcium and iron. All metals combine with oxygen to form metal oxides. Oxide of sodium is soluble in water but the oxides of magnesium and aluminium is insoluble in water.
Order of Reactivity
Na > Ca > Mg > Fe

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

Activity 3.10 (Page 42)

CAUTION: This Activity needs the teacher’s assistance.

  • Collect the samples of the same metals as in Activity 3.9.
  • Put small pieces of the samples separately ¡n beakers half-filled with cold water.
  • Which metals reacted with cold water? Arrange them in the increasing order of their reactivity with cold water.
  • Did any metal produce fire on water?
  • Does any metal start floating after some time?
  • Put the metals that did not react with cold water in beakers half-filled with hot water.
  • For the metals that did not react with hot water, arrange the apparatus as shown in Fig. and observe their reaction with steam.

NCERT Solutions for Class 10 Science Chapter 3 Metals and Non-Metals 20

  • Which metals did not react even with steam?
  • Arrange the metals in the decreasing order of reactivity with water.

Observation: Sodium metal reacts with cold water
NCERT Solutions for Class 10 Science Chapter 3 Metals and Non-Metals 21
Sodium metal produces fire on water because the reaction between sodium and water is so voilent and exothermic that the evolved hydrogen immediately catches fire.

Calcium starts floating, because the bubbles of hydrogen gas formed stick to the surface of the metal. Magnesium reacts with hot water and forms magnesium hydroxide and hydrogen.

Metals like iron and aluminium do not react either with cold or hot water. But they react with steam to form the metal oxide and hydrogen.
3Fe(s) + 4H2O(g) → Fe3O4(s) + 4H2(g)
Decreasing order of reactivity of different metals with water.
Na > Ca > Mg > Fe

Activity 3.11 (Page 44)

  • Collect all the metal samples except sodium and potassium again. If the samples are tarnished, rub them clean with sand paper.
    CAUTION: Do not take sodium and potassium as they react vigorously even with cold water.
  • Put the samples separately in test tubes containing dilute hydrochloric acid
  • Suspend thermometers in the test tubes, so that their bulbs are dipped in the acid.
  • Observe the rate of formation of bubbles carefully.
  • Which metals reacted vigorously with dilute hydrochloric acid?
  • With which metal did you record the highest temperature?
  • Arrange the metals in the decreasing order of reactivity with dilute acids.

Observation: The rate of formation of bubbles is fastest in the case of calcium and reaction is also most exothermic in this case.
This order of reactivity of metals with dilute HCl is:
Ca > Mg > Fe

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

Activity 3.12 (Page 44)

  • Take a clean wire of copper and an iron nail.
  • Put the copper wire in a solution of iron sulphate and the iron nail in a solution of copper sulphate taken in test tubes (Fig.).
  • Record your observations after 20 minutes.
  • In which test rube did you find that a reaction has occurred?
  • On what basis can you say that a reaction has actually taken place?
  • Can you correlate your observations for the Activities 3.9, 3.10 and 3.11?
  • Write a balanced chemical equation for the reaction that has taken place.
  • Name the type of reaction.

NCERT Solutions for Class 10 Science Chapter 3 Metals and Non-Metals 22
Observation : Reactive metals can displace less reactive metals from their compounds in solution or molten state.

Iron displaces copper from copper sulphate solution because iron is more reactive than copper cannot displace iron from, iron sulphate solution because copper is less reactive than iron.
Iron is more reactive than copper.
FeSO4(aq) + Cu(s) → No reaction
CuSO4(aq) + Fe(s) → FeSO4 + Cu(s)
This is a displacement reaction.

Sodium can displace calcium from calcium sulphate, calcium can displace magnesium from magnesium sulphate and magnesium can displace iron from iron sulphate solution.

Activity 3.13 (Page 48)

  • Take samples of sodium chloride, potassium iodide, barium chloride or any other salt from the science laboratory.
  • What is the physical state of these salts?
  • Take a small amount of a sample on a metal spatula and heat directly on the flame (Fig.). Repeat with other samples.
  • What did you observe? Did the samples impart any colour to the flame? Do these compounds melt?
  • Try to dissolve the samples in water, petrol and kerosene. Are they soluble?
  • Make a circuit as shown in Fig. and insert the electrodes into a solution of one salt. What did you observe? Test the other salt samples too in this manner.
  • What is your inference about the nature of these compounds?

Observation : All there salts are solid and some what hard due to the strong forces of attraction between the positive and negative ions.
NCERT Solutions for Class 10 Science Chapter 3 Metals and Non-Metals 23
NCERT Solutions for Class 10 Science Chapter 3 Metals and Non-Metals 24

NaCl crystals on heating break up with a crackling noise. The same noise is observed in all the cases and salts are dried. No colour is imparted by the sample to the flame. These salts are not melted.

These salts are fairly soluble in water but insoluble in petrol and kerosene.
Blub glow in all the salt solutions in water. It means ionic compounds conduct electricity and they are made of ions.

Activity 3.14 (Page 53)

  • Take three test tubes and place clean iron nails in each of them
  • Label these test tubes A, 13 and C. Pour some water in test tube A and cork it.
  • Pour boiled distilled water in test tube B, add about 1 mL of oil and cork it. The oil will float on water and prevent the aIr from dissolving in the water.
  • Put some anhydrous calcium chloride in test tube C and cork it. Anhydrous calcium chloride will absorb the moisture, if any, from the air. Leave these test tubes for a few days and then observe (Fig.).

NCERT Solutions for Class 10 Science Chapter 3 Metals and Non-Metals 25
Fig. : investigatIng the conditions under which Iron rusts. In tube A, both air and water present. In tube B, there is no air dissolved In the water. In tube C, the air is dry

Observation : We observe that iron nails rust in test tube A, but they do not rust in test tubes B and C. In the test tube A, the nails are exposed to both air and water. In the test tube B, the nails are exposed to only water, and the nails in test tube C are exposed to dry air. It suggested that air and water are necessary for corrosion of iron or a metal.

Class 10 Science Chapter 3 Metals and Non-Metals Additional Important Questions and Answers

Very Short Answer Type Questions

Question 1.
Give the name of a metal, which is in liquid state?
Answer:
Mercury.

Question 2.
Give the name of a non-metal, which is in liquid state?
Answer:
Bromine.

Question 3.
Give the name of a non-metal, which is in solid state?
Answer:
Iodine.

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

Question 4.
What is malleability?
Answer:
Metals can be hammered into sheets because layer of atoms slide over each other. This property of metals is called malleability.

Question 5.
Give two examples of soft metals.
Answer:
Sodium and Potassium.

Question 6.
What is ductility?
Answer:
The property of a metal in which they can be drawn into wires is called ductility.

Question 7.
Which is the most ductile metal?
Answer:
Gold.

Question 8.
Which are the most malleable metals?
Answer:
Gold and Silver

Question 9.
What is sonorocity?
Answer:
Metals produce a metallic sound when struck this property of metals is called sonorocity.

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

Question 10.
What is tensile strength?
Answer:
Metals can be stretched to some degree without breaking this property is called as tensile strength.

Short Answer Type Questions

Question 1.
What happens when:
(a) Sodium reacts with oxygen
(b) Magnesium reacts with oxygen
(c) Cu heated with oxygen
(d) Iron and Aluminium react with oxygen.
Give chemical reactions also.
Answer:
NCERT Solutions for Class 10 Science Chapter 3 Metals and Non-Metals 26
NCERT Solutions for Class 10 Science Chapter 3 Metals and Non-Metals 27

Question 2.
How ‘Al2O3‘ is an amphoteric oxide ?
Answer:
Some metal oxides which show acidic as well as basic character are known as amphoteric oxides, amphoteric metal oxides react with both adds as well as bases to produce salt and water. For example Al2O3 and ZnO.

Aluminium oxide is an amphoteric oxide because it reacts with acids as well as bases and form salts and water.
NCERT Solutions for Class 10 Science Chapter 3 Metals and Non-Metals 28

Question 3.
Are all metal oxides in soluble in water? If not, then given two examples of water soluble oxides, with chemical equations.
Answer:
No, Most metal oxides are insoluble in water but some of these dissolve to form alkalis. For example sodium oxide and potassium oxide dissolve in water to produce alkalis as follows :
NCERT Solutions for Class 10 Science Chapter 3 Metals and Non-Metals 29

Long Answer Type Questions

Question 1.
Name the chief ore of the following metals in the earth’s crust (i) aluminium (ii) calcium (iii) sodium (iv) mercury
How electrolytic reduction is carried out ?
Answer:
(i) Aluminium : Bauxite
(ii) Calcium : Lime stone
(iii) Sodium : Rock salt
(iv) Mercury : Cinnabar

Electrolytic reduction : Certain highly electropositive metals such as alkali metals (Na, K etc), alkaline earth metals and aluminium etc. are commonly extracted by the electrolysis of their fused salts. The process of extraction of metals by electrolysis process is called electrometallurgy. For example, sodiums extracted from fused sodium chloride by electrolysis as:
\(\mathrm{NaCl} \stackrel{\text { ionisation }}{\rightarrow} \mathrm{Na}^{+}+\mathrm{Cl}^{-}\)
At cathode : Na+ + e → Na
At anode : Cl → Cl + e
Cl + Cl → Cl2
Thus sodium is liberated at cathode and Cl2 gas liberated at Anode.

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

Multiple Choice Questions

Question 1.
The wires that carry current in your homes have a coating of:
(a) PVC
(b) BUNa-S
(c) Polybutadienes
(d) Bakelite
Answer:
(a) PVC

Question 2.
Choose non-metal from the following:
(a) S
(b) K
(c) Na
(d) Fe
Answer:
(a) S

Question 3.
Zinc can displace:
(a) Cu from CuSO4
(b) Ag from AgNO3
(c) Mg from MgSO4
(d) a and b
Answer:
(d) a and b

Question 4.
The metal used in tinning is:
(a) Sn
(b) Zn
(c) Cu
(d) Pt
Answer:
(a) Sn

Question 5.
A noble metal is:
(a) Pt
(b) Cu
(c) Zn
(d) Pd
Answer:
(a) Pt

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