Question 1:
Which of the following can be beaten into thin sheets?
- Zinc
- Phosphorus
- Sulphur
- Oxygen
Answer:
Zinc
Question 2:
Which of the following statements is correct?
- All metals are ductile.
- All non-metals are ductile.
- Generally, metals are ductile.
- Some non-metals are ductile.
Answer:
Generally, metals are ductile.
Question 3:
Phosphorus is a very __________ non-metal.
Answer:
Reactive
Question 4:
Metals are ___________ conductors of heat and
Answer:
Good, electricity
Question 5:
Iron is ____________ reactive than copper.
Answer:
More
Question 6:
Metals react with acids to produce ____________ gas.
Answer:
Hydrogen
Question 7:
Generally, non-metals react with acids.
- TRUE
- FALSE
Answer:
FALSE
Question 8:
Sodium is a very reactive metal.
- TRUE
- FALSE
Answer:
TRUE
Question 9:
Copper displaces zinc from zinc sulphate solution.
- TRUE
- FALSE
Answer:
FALSE
Question 10:
Coal can be drawn into wires.
- TRUE
- FALSE
Answer:
FALSE
Question 11:
Some properties are listed in the following Table. Distinguish between metals and non-metals on the basis of these properties.
Answer:
Differences between metals and non-metals are:
Question 12:
Give reasons for the following.
(a) Aluminium foils are used to wrap food items.
(b) Immersion rods for heating liquids are made up of metallic substances.
(c) Copper cannot displace zinc from its salt solution.
(d) Sodium and potassium are stored in kerosene.
Answer:
(a) Aluminium foils are used to wrap food items because aluminium is malleable and less reactive to air and water.
(b) Immersion rods used for heating liquids are made up of metallic substances because metals are good conductors of heat and electricity.
(c) Only a more reactive metal can displace a less reactive metal from its solution. Copper is a less reactive metal than zinc. Therefore, copper cannot displace zinc from its salt solution.
(d) Sodium and potassium are very reactive metals. They react vigorously with water to form oxides or hydroxides. Therefore, they are stored in kerosene oil.
Question 13:
Can you store lemon pickle in an aluminium utensil? Explain.
Answer:
No, lemon pickle cannot be stored in an aluminium utensil because lemon contains citric acid which reacts with aluminium to produce a salt of aluminium and hydrogen gas. This will spoil the food and make it unfit for eating.
Question 14:
Match the substances given in Column A with their uses given in Column B.
- Gold
- Iron
- Aluminium
- Carbon
Answer:
(i). (b), (ii). (c), (iii). (a), (iv). (d)
Question 15:
What happens when
(a) Dilute sulphuric acid is poured on a copper plate?
(b) Iron nails are placed in copper sulphate solution?
Write word equations of the reactions involved.
Answer:
Question 16:
Saloni took a piece of burning charcoal and collected the gas evolved in a test tube.
(a) How will she find the nature of the gas?
(b) Write down word equations of all the reactions taking place in this process.
Answer:
Question 17:
One day Reeta went to a jeweller’s shop with her mother. Her mother gave an old gold jewellery to the goldsmith to polish. Next day when they brought the jewellery back, they found that there was a slight loss in its weight. Can you suggest a reason for the loss in weight?
Answer:
Jewellers usually use a strong acidic solution to polish the gold jewellery. When the gold is dipped in the acidic solution, it reacts with the acid. A small amount of the gold dissolves in the acid from the outer layer of the jewellery. Thus, there is a slight loss in the weight of the jewellery.