Exercises
1) Which of the following can be beaten into thin sheets?
(a) Zinc (b) Phosphorus (c) Sulphur (d) Oxygen
ANSWER 🙁 a) Zinc
2) Which of the following statements is correct?
(a) All metals are ductile.
(b) All non-metals are ductile.
(c) Generally, metals are ductile.
(d) Some non-metals are ductile.
ANSWER:-c) Generally, metals are ductile
3) Fill in the blanks:
(a) Phosphorus is a very __reactive__ non-metal.
(b) Metals are __good__ conductors of heat and__electricity__.
(c) Iron is __more__ reactive than copper.
(d) Metals react with acids to produce __hydrogen__ gas.
4) Mark ‘T’ if the statement is true and ‘F’ if it is false.
(a) Generally, non-metals react with acids. ( )
(b) Sodium is a very reactive metal. ( )
(c) Copper displaces zinc from zinc sulphate solution. ( )
(d) Coal can be drawn into wires. ( )
ANSWER:-
a)F
b)T
c)F
d)F
5) Some properties are listed in the following Table. Distinguish
between metals and non-metals on the basis of these properties.
between metals and non-metals on the basis of these properties.
Properties. Metals Non-metal
1. Appearance
2. Hardness
3. Malleability
4. Ductility
5. Heat
Conduction
6. Conduction of Electricity
ANSWER:-
Metals-Lustrous, hard, Can be beaten into thin sheets; Can be beaten into wires, Good
conductors of heat, Good conductors of electricity.
conductors of heat, Good conductors of electricity.
Non-Metals-dull, soft, Cannot be beaten into thin sheets, Cannot be beaten into wires, Poor
conductors of heat, Poor conductors of electricity.
conductors of heat, Poor conductors of electricity.
6) 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.
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 metal is
malleable. Therefore, it can be beaten into thin foils.
malleable. Therefore, it can be beaten into thin foils.
(b) Metals are good conductors of heat and electricity. Therefore,
immersion rods for heating liquids are made of metallic substances.
immersion rods for heating liquids are made of metallic substances.
(c) A metal can displace a less reactive metal from its salt in an
aqueous solution. But zinc is more reactive than copper. Therefore,
copper cannot displace zinc from its salt solution.
aqueous solution. But zinc is more reactive than copper. Therefore,
copper cannot displace zinc from its salt solution.
d) Sodium and potassium are stored in kerosene because they are
highly reactive elements. They can easily catch fire even
when in contact with air.
highly reactive elements. They can easily catch fire even
when in contact with air.
7) Can you store lemon pickle in an aluminium utensil? Explain.
ANSWER:-Lemon pickle cannot be stored in aluminium utensils because lemon pickle contains
acids, which can react with aluminium (metal)
liberating hydrogen gas. This can lead to the spoiling
of the pickle.
acids, which can react with aluminium (metal)
liberating hydrogen gas. This can lead to the spoiling
of the pickle.
8) Match the substances given in Column A with their uses given
in Column B.
in Column B.
A B
(i) Gold (a) Thermometers
(ii) Iron (b) Electric wire
(iii) Aluminium. (c)
Wrapping food
Wrapping food
(iv) Carbon (d) Jewellery
(v) Copper (e) Machinery
(vi) Mercury (f) Fuel
ANSWER:-
A. B
(i) Gold d)
Jewellery
Jewellery
(ii) Iron
e) Machinery
e) Machinery
(iii) Aluminium. c) Wrapping food
(iv) Carbon f)
Fuel
Fuel
(v) Copper b) Electric wire
(vi) Mercury a) Thermometers
9) 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:-a) When dilute sulphuric acid is poured on a copper plate, the
copper metal reacts with sulphuric acid to liberate hydrogen gas.
copper metal reacts with sulphuric acid to liberate hydrogen gas.
(b) Iron being more reactive displaces copper from copper sulphate
solution. In this reaction, the blue colour of copper sulphate fades and there
is deposition of copper on the iron nail.
solution. In this reaction, the blue colour of copper sulphate fades and there
is deposition of copper on the iron nail.
10) Saloni took a piece of burning charcoal and collected the
gas evolved in a test tube.
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.
in this process.
ANSWER 🙁 a) Add a few drops of water in the test tube containing gas. Now, cover the test
tube and shake it well. After shaking, test the solution with blue litmus
and red litmus. It will turn blue litmus red. Thus,
the gas is acidic in nature.
tube and shake it well. After shaking, test the solution with blue litmus
and red litmus. It will turn blue litmus red. Thus,
the gas is acidic in nature.
(b) Charcoal reacts with oxygen to form carbon dioxide gas. Carbon
dioxide reacts with water to form carbonic acid, which turns blue litmus paper
red.
dioxide reacts with water to form carbonic acid, which turns blue litmus paper
red.