"AKC SCIENCE CLASSES"
CLASS 10 TH (CBSE AND MP BOARD)
CHAPTER 03
METALS AND NON-METALS
EXERCISES QUESTIONS AND ANSWER
Q.01:- Which of the following pairs will give displacement reactions?
(a) NaCl solution and copper metal.
(b) MgCl2 solutions and aluminium metal.
(c) FeSO4 solution and silver metal.
(d) AgNO3 solution and copper metal.
Ans:- (d) AgNO3 solution and copper metal.
2AgNO3(aq) + Cu(s) ⟶ Cu(NO3)2(aq) + 2Ag(s)
Q.02:- Which of the following methods is suitable for preventing an iron frying pan from rusting?
(a) Applying grease.
(b) Applying paints.
(c) Applying a coating of zinc
(d) all of the above.
Ans:- (d) all of the above.
Q.03:- An element reaches 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.
Ans:- (a) Calcium.
Q.04:- Food cans are coated with in 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.
Ans:- (c) Zinc is more reactive than tin.
Q.05:- You are given a hammer, a battery, a bulb, wires and a switch.
(a) How could you use them to distinguish between samples of metals and non-metals?
(b) Assess the usefulness of these tests in distinguishing between metals and non-metals.
Ans:- (a) Metals can be spread into sheets with the help of hammer while non-metals give powder. When metals are connected into circuit using battery, bulb, wires and a switch, current passes through the circuit and the bulb glows.
(b) Hammer is a reliable method because no non-metal can be spread into sheet because non-metal carbon in the form of graphite is a conductor of electricity.
Q.06:- What are amphoteric oxides? Give two examples of amphoteric oxides.
Ans:- Such oxides which react both with acids as well as bases to form salts and water are known as amphoteric oxides. For examples aluminium oxide and zinc oxide.
ZnO + 2HCl ⟶ ZnCl2 + H20
ZnO + 2NaOH ⟶ Na2ZnO2 + H20
Q.07:- Name two metals which will displaces hydrogen from dilute acids, and two metals which will not.
Ans:- (ⅰ) Metals like sodium and magnesium displace hydrogen from dilute acids (metals above hydrogen in the activity series).
(ⅱ) Metals below hydrogen in the activity series like copper, silver do not displace hydrogen from dilute acids.
Q.08:- In the electrolytic refining of a metal M, what would you take as the anode, the cathode and the electrolyte?
Ans:- Cathode ⟶ pure metal.
Anode ⟶ Impure metal.
Electrolyte ⟶ Metal salt solution
Q.09:- Pratyush took sulphur powder on a spatula and heated it. He collected the gas evolved by inverting a test tube over it, as shown in figure 3.1.
- dry litmus paper?
- moist litmus paper?
(b) Write a balanced chemical equation for the reaction taking place.
Ans:- (a)
- Dry litmus paper ⟶ No action.
- Moist litmus paper ⟶ becomes red.
Sulphur Sulphur Sulphurous
dioxide acid
Q.10:- State two ways to prevent the rusting of iron.
Ans:- Ways to prevent rusting of iron :-
(a) By painting.
(b) By Galvanising.
Q.11:- What type of oxides are formed when non-metals combine with oxygen?
Ans:- Acidic Oxides.
Q.12:- 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 sulphide ores are usually converted into oxides during the process of extraction.
Ans:- (a) Platinum, gold and silver are non-reactive and give shining surface.
(b) Sodium, potassium and lithium are very reactive and catch fire when exposed to air.
(c) Aluminium forms a non-reactive layer of aluminium oxide on its surface.
(d) It is easier to reduce oxides into metal
Q.13:- You must have been tarnished copper vessels being cleaned with lemon or tamarind juice. Explain why these sour substances are effective in cleaning the vessels.
Ans:- Copper vessles get a green deposit of copper carbonate. Since copper carbonate. Since copper carbonate dissolves in mild acids of lemon or tamarind juice, copper vessels are cleaned.
Q.14:- Differentiate between metal and non-metal on the basis of their chemical properties.
Ans:-
| SL No. | Metals | Non-metals | |
|---|---|---|---|
| 1 | Metals form basic oxides, some of which form alkalies. | Non-metals form acidic or neutral oxides | |
| 2 | Metals replace hydrogen from acids and from salts. | Non-metals do not replace hydrogen from acids. | |
| 3 | With chlorine, metals from chlorides which are electrovalent. | With chlorine non-metals form chloride which are covalent. | |
| 4 | With hydrogen few metals form hydrides which are electrovalent. | With hydrogen non-metals form many stable hydrides which are covalent. |
Q.15:- A man went 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 detection to find out the nature of the solution he had used?
Ans:- Aqua regia ⟶ a mixture of concentrated hydrochloric acid and concentrated nitric acid in the ratio of 3 : 1, since it dissolves gold.
Q.16:- Give reasons why copper is used to make hot water tanks and not steel (an alloy of iron).
Ans:- Iron (steel) reacts with hot water but copper does not.
3Fe(s) + 4H2O ⟶ Fe3O4(s) + 4H2(g)
Hot
Cu(s) + H20 ⟶ No. reaction.
Hot
