MG SCHOOL EDUCATION: Class 10 Science Chapter 3 Metals and non metals

Class 10 Science

Chapter 3 Metals and non metals

Previous years appeared questions

Multiple Choice Questions

1. The possible chemical reaction among the following is (June 2019)

Ans: C

2. The electronic configuration of element X is 2, 8, 8, 1 and the electronic configuration of element Y is 2, 8, 7. Then the type of bond formed between these two elements is (March 2019)

(A) covalent bond (B) hydrogen bond

Ans: (D) ionic bond

3. The amphoteric oxide among the following is (KSEEB MQP 2021)

A) Potassium oxide B) Sodium oxide

C) Calcium oxide D) Zinc oxide

Ans: D) Zinc oxide

4. Which of the following will give displacement reactions? (KREIS Midterm - 22)

A) NaCl solution and Copper metal.

B) MgCl2 solution and Aluminium metal.

C) FeSO4 solution and Silver metal.

D) AgNO3 solution and Copper metal.

Ans: D) AgNO3 solution and Copper metal.

5. Silver articles become black on prolonged exposure to air; this is due to the formation of (KREIS Midterm-22)

a) silver sulphide

b) silver nitride

c)silver carbonate

d) silver oxide

Ans: a) silver sulphide

One Marks Questions

1. What are amphoteric oxides ? (Sep 2020)

Ans. : Metallic oxides that show both acidic and basic behaviour are called amphoteric oxides.

2. An iron ring is to be coated with copper. How can we do this without using electricity ? (March 2020)

Ans. :

Iron ring should be dipped in copper sulphate solution. Iron displaces copper from copper sulphate solution and copper is coated on iron ring.

3. What is roasting in metallurgy ? (March 2019)

Ans:

Roasting is a process of heating a sulfide ore to a high temperature in the presence of air.

4. Ionic compounds have high melting points. Why? ( KSEEB MQP 2020)

Ans:

Because the ions are held together tightly by strong forces of attraction between the oppositely charged ions.

5. What is corrosion? Give an example. (KREIS Midterm-22)

Ans:

When a metal is attacked by substances around it such as moisture, acids, etc., it is said to corrode and this process is called corrosion.

For example- Rusting of iron.

Two Marks Questions

1. Draw the diagram to show the arrangement of the apparatus used for testing the conductivity of salt solution and label ‘graphite rod’. ( March 2022)

Ans. : Testing the conductivity of a salt solution :

2. Give reason :

a) Metals are used in making cooking vessels.

b) Sodium metal is stored in kerosene. ( March 2022)

Ans. :

a) Because, metals are good conductors of heat / having high melting points / property of malleability. ( Any one )

b) Sodium metal vigorously reacts with atmospheric oxygen and water, but not with kerosene.

3. What is corrosion ? How can it be prevented ? ( March 2020)

Ans. :

> When a metal is attacked by substances around it such as moisture, acids the phenomenon is called corrosion. 1

> Preventions : Rusting can be prevented by painting, oiling, greasing, galvanising, chrome plating, anodising alloys. ( Any two )

4. Write any two differences between chemical properties of metals and non-metals. (March 2020)

Ans. :

Chemical properties of metals :

> Liberates H2 from dilute acids.

> Metallic oxides are basic in nature. Chemical properties of non-metals :

> Do not liberate H2 from dilute acids.

> Oxides of non-metals are acidic in nature.

5. Give reason :

a) When a calcium metal reacts with water, the liberated hydrogen gas does not catch fire.

b) Ionic compounds have high melting and boiling points. ( March 2022)

Ans. :

a) The reaction of calcium with water is less violent. The heat evolved is not sufficient for the hydrogen to catch fire.

b) Because a considerable amount of energy is required to break the strong inter-ionic attraction.

6. Draw the diagram of the apparatus used in refining of copper from copper sulphate solution. Label the following parts : i) Cathode ii) Anode mud. (Sep 2020)

7. Which physical properties are used in the following situations ?

i) Gold is used to make ornaments

ii) Nickel is used in strings of guitar. (March 2020)

Ans. :

i) Shining surface / Metallic lustre Ductility Malleability ( Any two )

ii) Sonorous Ductility.

8. What are malleability and ductility with respect to metals ? (June 2019)

Ans:

> Malleability is the property of a metal by which it can be beaten into thin sheets and foils.

> Ductility is the property of a metal by which it can be drawn into wires.

9. (i) Write the balanced chemical equation for the reaction taking place when aluminium reacts with dilute hydrochloric acid.

(ii) Hydrogen gas is not liberated when a metal reacts with concentrated nitric acid. Give reason. (June 2019)

Ans:

(i) 2Al(s)+6HCl(aq)→2AlCl3(aq)+3H2(g)

(ii) Hydrogen gas is not evolved when a metal reacts with nitric acid. It is because HNO3 is a strong oxidising agent. It oxidises the H2 produced to H2O.

Three Marks Questions

1. Strips of zinc, iron, magnesium and copper are taken in the test tubes A, B, C and D respectively. Same quantity of ferrous sulphate solution is added to these test tubes. In which test tubes chemical reaction will occur ? Why ? Write the chemical equations for the reactions taking place here.

Ans. :

> Chemical reaction occurs in test tubes A and C.

>Because zinc and magnesium are more reactive than iron. Zinc and magnesium are found above iron in the reactivity series of metals.

>Zinc + Ferrous sulphate → Zinc sulphate + Iron

>Zn + FeSO4 → ZnSO4+ Fe

>Magnesium + Ferrous sulphate → Magnesium sulphate + Iron

>Mg + FeSO4 → MgSO4+ Fe

2. Draw the diagram of the arrangement of apparatus to show the action of steam on a metal. Label the following parts : (i) Metal sample (ii) Delivery tube. (June 2019)

Ans:

7. Explain how is zinc obtained from sulphide and carbonate ores? (KREIS Midterm 2022)

Ans:

Zinc sulfide is oxidized to zinc oxide by a process of roasting. In this process, oxygen is supplied in high amounts. The gas released is sulfur dioxide.

2ZnS(s)+3O2(g) → 2ZnO(s)+2SO2(g)

Zinc carbonate is oxidized to zinc oxide by a process of calcination. I n this process, oxygen is supplied in limited amount. the gas released is carbon dioxide. Or

2ZnCO3(s) → ZnO(s)+CO2(g)

The oxide obtained from both the ores, is now reduced with the help of coke.

ZnO(s)+C(s) → Zn(s)+CO(g)

Four Marks Questions

1. Mention the difference between calcination and roasting. How these processes are used in the extraction of zinc ? Explain with the help of Total chemical equations. After these processes is reduction necessary to obtain zinc ? Why ? (March 2020)

Ans. :

> Carbonate ores are converted into oxides by heating strongly in limited air. This process is known as calcination.

> Sulphide ores are converted into oxides by heating strongly in the presence of excess of air.

> This process is known as roasting. 2 1 When ZnCO3 undergoes calcination ZnO is formed.

2. Give reason :

(i) Ionic compounds in solid state do not conduct electricity, whereas in molten state are good conductors of electricity.

(ii) Silver articles when exposed to air gradually turn blackish.

(iii) Chemical reaction does not take place when copper is added to iron sulphate solution. (March 2019)

Ans:

(i)

> When Ionic are in a solid state, the ions cannot move and thus there is no flow of charge

> when molten, the anions and cations are free to move they conducts electricity.

(ii)

> Because the silver metal reacts with sulphur present in the atmosphere and forms silver sulphide. because of which they appear dull and black.

(iii)

> Copper being less reactive than iron, is placed at the bottom of the reactivity series, below iron. Therefore, a displacement reaction does not take place

3. Give reason :

(i) “Alloys of iron are more useful when compared to pure iron.”

(ii) Copper loses its brown layer gradually when exposed to air.

(iii) Aluminium oxide is called amphoteric oxide. (March 2019)

Ans:

(i) Alloy of iron is more useful because the pure iron is very soft and cannot be use but mixing with other metal give strength to the metal and can make different metals.

(ii) Copper reacts with moist carbon dioxide in air to form copper carbonate and as a result, copper vessel loses its shiny brown surface forming a green layer of copper carbonate.

(iii) Metal oxides which react with both acids and as well as bases to produce salt and water are called amphoteric oxides. Aluminium oxide react both with bases and acids.

4. a) Ionic compounds in solid state do not conduct electricity, but in molten state are good conductors of electricity. Why ?

b) Write the formation of magnesium chloride (MgCl2 ) with the help of electron dot structure. (KSEEB MQP 2021)

Ans:

> When Ionic are in a solid state, the ions cannot move and thus there is no flow of charge

> when molten, the anions and cations are free to move they conducts electricity.

Mg --> Mg+2 + 2e

2, 8, 2 2, 8

Cl + 2e --> Cl-2

2, 8, 7 2, 8, 8

Magnesium donates one electron each with two chlorine atoms resulting in the formation of magnesium chloride.

5. a) What are alloys? Name the alloy which has lead and tin as its constituent and write one of its uses.

b) What is an amphoteric oxide? Write any two chemical properties of metals ( KSEEB MQP 2020)

Ans:

> Alloys are the homogeneous mixture of two or more metals or a non metal.

> Solder is the alloy which has lead and tin as it's constituent .

> One use of solder is used to create electrical joints

> Oxides of metals which have both acidic as well as basic behaviour are known as amphoteric oxides

> Many metals produce metal oxide by burning in the oxygen of the air. Highly reactive metals react violently when they’re burnt in oxygen.

> Metals produce metal oxide and hydrogen gas while reacting with water.

> Soluble metal oxides dissolve in water and create metal hydroxide.

6. Write any four differences between metals and non-metals on the basis of chemical properties? ( KREIS Midterm 2022)

Ans:

Metals:

> Metal oxides are basis in nature

> Metal displace hydrogen from dil. Acid

> Metals form chlorides which are ionic compounds

> They displace hydrogen from water

Non-Metals:

> Non-Metal oxides are acidic in nature

> They connot do so.

> Non-Metals form chlorides which are covalent compounds

> They cannot do so.

7. Write any four general properties of ionic compounds.

b) Name the following:

i) Liquid non-metal at room temperature.

ii) Most ductile metal. (KREIS Midterm-22)

Ans:

> They're hard and brittle.

> They have high melting points and high boiling points

> They are soluble in water but insoluble in organic solvents.

> They conduct electricity when dissolved in water or when melted.

i) Bromine

ii) Gold

5 Marks questions

1. a) Explain the formation of ionic bond between sodium atom and chlorine atom. [ Atomic number of sodium is 11, Atomic number of chlorine is 17 ]

b) List any four general properties of ionic compounds. ( june 2022)

Ans. :

a) Electronic configuration of sodium atom is 2, 8, 1

Electronic configuration of chlorine atom is 2, 8, 7

To have stable octet configuration sodium loses its one valence electron, thus forms sodium cation ( Na+ ) and chlorine receives one electron to its valence shell, thus forms chloride anion ( Cl− ).

Due to the electrostatic force between oppositely charged Na+ and Cl− ions sodium chloride ( NaCl ) forms.