Chapter 27: METALS AND NON-METALS

Chapter 27: Metals and Non-Metals Class 10 Science and Technology (212) NIOS Textbook Solutions

Chapter 27. METALS AND NON-METALS

INTEXT QUESTIONS 27.1

1. Which properties of gold allows it to make ornaments?

Answer: The properties of gold that make it suitable for making ornaments are:

(i) Malleability: Gold can be hammered into very thin sheets without breaking.

(ii) Ductility: It can be drawn into thin wires for making chains and intricate jewellery.

2. Name a few metals which are found in free state?

Answer: few metals that are found in the free (native) state because they are very unreactive are gold (Au) , silver (Ag) and platinum (Pt)

3. Metals are generally very hard. Name the metal which is soft like wax?

Answer: The metal that is soft like wax is Sodium.

4. Name a non-metal which is a good conductor of electricity.

Answer: The non-metal that is a good conductor of electricity is graphite.

5. Name two metals which show malleability and ductility.

Answer: Two metals that show both malleability and ductility are gold and silver.

INTEXT QUESTIONS 27.2

1. Under what conditions there are more chances for iron to be rusted?

Answer: Iron has more chances of rusting when it is exposed to both air (oxygen) and moisture (water). Rusting occurs faster in humid or damp conditions.

2. Why metals are electropositive but non-metals are electronegative in nature?

Answer: Metals have tendency to lose electrons and get converted into a positive ion and therefore are electropositive. Non-metals have tendency to take electron and get converted into a negatively charged ion and therefore are electronegative.

3. Name a metal oxide which reacts with an acid as well as with a bases?

Answer: Aluminium oxide (Al₂O₃) and Zinc oxide (ZnO) are amphoteric oxides. They react with both acids and bases.

4. When zinc reacts with sodium hydroxide what is the product? Write the equation.

Answer: When Zinc reacts with Sodium hydroxide (NaOH), it forms Sodium zincate and Hydrogen gas.

Chemical equation:

Zn+2NaOH→Na2ZnO2+H2

5. Write the formula of rust.

Answer: The chemical formula of rust is Hydrated iron(III) oxide (Fe₂O₃·xH₂O) .

INTEXT QUESTIONS 27.3

1. What will happen if you keep a solution of copper (II) sulphate in an iron vessel? Explain the observation and give suitable explanation.

Answer: If a solution of Copper(II) sulphate (CuSO₄) is kept in an iron vessel, iron displaces copper from the solution because iron is more reactive than copper.

Chemical equation: Fe+CuSO4→FeSO4+Cu

2. What will happen if you keep a solution of silver nitrate in a copper vessel? Explain the observation.

Answer: When silver nitrate is kept in copper vessel, copper will replace silver as copper is above silver in the activity series and a hole is expected in the bottom of copper vessel.

Chemical equation: Cu+2AgNO3→Cu(NO3)2+2Ag

3. An element reacts with oxygen to form an oxide which dissolves in water to form a solution that turns red litmus blue. The oxide dissolves in dil. HCI. Identify the element as metal or non-metal.

Answer: The oxide of the element turns red litmus blue, which shows that it is a basic oxide. This is further confirmed because the oxide reacts with dilute HCl to form salt and water. Since basic oxides are formed by metals, the element must be a metal.

4. Give an example of a metal which

(a) is a liquid at room temperature.

(b) can be easily cut with a knife.

(d) poorest conductor of electricity.

Answer: (a) Hg (mercury) is metal which is liquid at room temperature

(b) Sodium metal can be cut easily with knife

(d) Iron is poorest conductor of electricity.

5. Write the formula of the oxide of magnesium formed on burning of magnesium ribbon in oxygen?

Answer: When Magnesium ribbon is burned in oxygen, it forms Magnesium oxide (MgO).

2Mg(s) + O2 (g)→ 2MgO(s)

6. Name the hydroxide of magnesium formed when magnesium oxide reacts with hot water?

Answer: When Magnesium oxide (MgO) reacts with hot water, it forms Magnesium hydroxide (Mg(OH)₂).

Chemical equation: MgO+H2O→Mg(OH)2

Name of the hydroxide: Magnesium hydroxide (Mg(OH)₂).

7. What happens when sodium metal reacts with water in cold? Write the reaction for the same?

Answer: When Sodium reacts with cold water, it reacts vigorously to form Sodium hydroxide (NaOH) and Hydrogen gas.

Chemical equation: 2Na+2H2O→2NaOH+H2

8. Define activity series of metals? Write a reaction when zinc granules are added to copper sulphate solution?

Answer: When the metals are arranged in the decreasing order of their reactivity, a series is obtained, this series is called activity series. Metals in the upper position of the series can replace the metal in lower position from their aqueous solution.

When zinc granules are added to copper sulphate solution, then the chemical equation is

Zn+CuSO4→ZnSO4+Cu

Zn is above copper in activity series therefore it (Zn) will replace copper from the solution.

9. What is the difference between ‘mineral’ and ‘ore’?

Answer: The difference between mineral and ore is:

Mineral	Ore
Naturally occurring homogeneous inorganic substances are called minerals.	Minerals from which metals can be extracted profitably are called ores.
A mineral may or may not contain enough metal for economical extraction.	An ore contains enough metal to allow economical extraction.
Every mineral is not an ore.	Every ore is a mineral.

TERMINAL EXERCISES

1. Name two precious metals used in making ornaments and write names of two important properties of these metals.

Anwer: The two precious metals used in making ornaments are gold and silver.

Two important properties of these metals are:

(i) Malleability: They can be beaten into thin sheets.

(ii) Ductility: They can be drawn into thin wires.

2. Name two non-metals which are commonly available and name their two important properties.

Answer: The two commonly available non-metals are carbon and sulphur

Two important properties of non-metals are:

(i) They are poor conductors of heat and electricity (except graphite).

(ii) They are brittle (not malleable or ductile).

3. Write four physical properties of metals.

Answer: Four physical properties of metals are:

(i) Metals are lustrous (shiny).

(ii) Metals are malleable (can be beaten into thin sheets).

(iii) Metals are ductile (can be drawn into thin wires).

(iv) Metals are good conductors of heat and electricity.

4. Write four physical properties of non-metals.

Answer: Four physical properties of non-metals are:

(i) Non-metals are generally dull (non-lustrous).

(ii) Non-metals are brittle .

(iii) Non-metals are poor conductors of heat and electricity (except Graphite).

(iv) Non-metals are non-sonorous .

5. How would you differentiate between a metals and a non-metal.

Answer: The difference between a metals and a non-metal are:

Metals	Non-metals
Metals are generally hard.	Non-metals are generally soft.
They are malleable and ductile.	They are brittle (not malleable or ductile).
They are good conductors of heat and electricity.	They are poor conductors of heat and electricity (except Graphite).
They are lustrous (shiny).	They are generally non-lustrous (dull).
They are sonorous (produce a ringing sound when struck).	They are non-sonorous.
They usually form basic or amphoteric oxides.	They usually form acidic or neutral oxides.

6. Write reaction of metals with the following:

(a) water (b) air or oxygen (c) acids

Answer: (a) Metals react with water : Sodium react with water to form Sodium hydroxide and hydrogen gas.

2Na+2H2O→2NaOH+H2

(b) Metals react with air or oxygen : Sodium react with oxygen to form metal oxides.

4Na+O2→2Na2O

Mg+2HCl→MgCl2+H2

7. What are three types of oxides of metals?

Answer: The three types are basic, amphoteric and neutral oxides.

8. Name four uses of metals.

Answer: Four important uses of metals are:

(i) Iron and steel are used to make machines.

(ii) Gold, silver and platinum metals are used to make jewellaries due to their luster, high malleability and inert nature.

(iii) Many metals like iron ,copper and aluminium are used to make containers.

(iv) Zinc, lead, mercury, lithium are used to make cells and batteries.

9. Write four uses of non-metals.

Answer: Four important uses of non-metals are:

(i) White phosphorous as is used in the match industry.

(ii) Silicon is used in making transistors, chips for computers and photovoltaic cells.

(iii) Hydrogen is used in manufacturing of ammonia gas which is further used in the manufacturing of urea (fertilizer).

(iv) Sulphur is used in agriculture to control fungus and pests.

10. Define the following:

(a) Brittleness (b) Sonorous nature.

Answer: (a) Brittleness is the property of a substance by which it breaks easily on applying force or hammering.

(b) Sonorous nature is the property of metals by which they produce a ringing sound when struck.

11. Name two metals which are most malleable and ductile. Also define:

(a) Malleability (b) Ductility (c) brittleness (d) Tensile nature

Answer: Two most malleable and ductile metals are gold and silver.

(a) Malleability is the property of a metal by which it can be beaten into thin sheets.

(b) Ductility is the property of a metal by which it can be drawn into thin wires.

(c) Brittleness is the property of a substance (usually non-metals) by which it breaks easily on applying force or hammering.

(d) Tensile nature is the ability of a material (especially metals) to withstand pulling or stretching force without breaking.

12. Write uses of the following metals:

(a) Pt (b) Au (c) Na (d) Ag (e) Ni

Answer: (a) Platinum (Pt) is used in jewellery and also in catalytic converters in vehicles due to its high resistance to corrosion.

(b) Gold (Au) is used for making ornaments, coins, and electronic components because it is highly malleable and does not corrode.

(c) Sodium (Na) is used in the chemical industry for making compounds like sodium hydroxide and also in street lamps (sodium vapour lamps).

(d) Silver (Ag) is used in jewellery, coins, and mirrors because of its high reflectivity and conductivity.

(e) Nickel (Ni) is used for plating metals to prevent corrosion and also in making alloys like stainless steel.

13. What is corrosion? How will you prevent it?

Answer: Corrosion is the slow deterioration of metals due to their reaction with air, moisture, or chemicals in the surroundings. For example, iron forms rust when exposed to air and water.

Corrosion can be prevented by:

(i) Painting or coating the metal surface prevents contact with air and water.
(ii) Oiling or greasing prevents exposure to moisture.
(iii) Galvanisation is the coating of iron with Zinc.
(iv) Electroplating is done using non-reactive metals like chromium or nickel.
(v) Alloying is the process of making alloys like stainless steel to increase resistance.

14. You are provided atomic number of metal X, Y and Z (not real names) in the following table. Based on electronic configuration predict whether they fall in the category of metal or non-metal.

Atomic number

Metal

Metal or non-metal

…………………..

……………………

Answer:

Atomic number

Electronic configuration

Metal

Metal or non-metal

2.7

2.8.2

2.8.6

Non-metal

Metal

Non-metal

15. Complete and balance the following reactions:

(i) Mg(s) + H2SO4 (aq) → ............... + ...............

(ii) Fe(s) + H2O (steam) → ............... + ...............

(iii) Na(s) + H2O(l) → ............... + ...............

Answer: (i) Mgs+ H2SO4 aq→ MgSO4+H2

(ii) Fes+ H2O steam→Fe3O4+4H2

(iii) Nas+ H2Ol→2NaOH+H2

16. Write names and formulas of different oxides of nitrogen.

Answer: Different oxides of nitrogen along with their names and formulas are:

(i) Nitric oxide (Nitrogen monoxide) → NO

(ii) Nitrogen dioxide → NO₂

(iii) Nitrous oxide → N₂O

(iv) Dinitrogen trioxide → N₂O₃

(v) Dinitrogen tetroxide → N₂O₄

(vi) Dinitrogen pentoxide → N₂O₅

17. Which one of the following oxides is not acidic?

(a) CO (b) CO2 (c) SO2 (d) SO3

Answer: (a) CO

[ Carbon monoxide (CO) is a neutral oxide, not acidic.]

18. Write at least one important use of the following chemicals

(a) H3PO4 (b) H2SO4 (c) NH3 (d) Water gas

Answer: (a) Phosphoric acid (H₃PO₄) is used in making fertilisers (like ammonium phosphate).

(b) Sulphuric acid (H₂SO₄) is used in car batteries (lead-acid batteries) and also in fertiliser production.

(d) Water gas is used as a fuel and also in the manufacture of hydrogen gas.

19. Identify the non-metal from the following which is used for fungus control in agriculture:

(a) Phosphorus (b) Sulphur (c) Iodine

Answer: (b) Sulphur.

[Sulphur is used as a fungicide in agriculture to control fungal infections on crops.]

20. Whch of the following metals is not used in making cell/battery?

(a) Zn (b) Pb (c) Hg (d) Na

Answer: (d) Na

[Sodium is not used in ordinary batteries because it is highly reactive and difficult to handle safely.]

21. Which of the following non-metals is a liquid at room temperature

(a) Bromine (b) Phosphorous (c) Sulphur (d) Iodine

Answer: (a) Bromine.

[ Bromine is the only non-metal that exists as a liquid at room temperature.]

22. Complete the following reactions

(i) Al2O3 (s) + ............. → 2NaAlO2+ H2O (l)

(Sodium aluminate)

(ii) CaO(s) + ............. → Ca(OH)2

(iii) Sn(s) + .............+ H2O (l) → Na2SnO3

(Sodium stannate)

Answer: (i) Al2O3+2NaOH→2NaAlO2+H2O

(ii) CaO+H2O→ Ca(OH)2

(iii) Sn+2NaOH+H2O→Na2SnO3+2H2

23. Define Roasting and Calcination.

Answer: Roasting is the process in which sulphide ores are heated strongly in the presence of excess air (oxygen) to convert them into oxides.

Example : 2ZnS+3O2 heat 2ZnO+2SO2

Calcination is the process in which carbonate ores or hydrated ores are heated strongly in the absence or limited supply of air to convert them into oxides.

Example : ZnCO3 heat ZnO+CO2

Posted 3 weeks ago

Chapter 27: METALS AND NON-METALS

Chapter 27: Metals and Non-Metals Class 10 Science and Technology (212) NIOS Textbook Solutions

Chapter 27. METALS AND NON-METALS

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