Metals and Non-metals
Class X, NCERT Solutions of Chapter 3 Science InText Questions
CBSE NCERT Solutions: InText Questions (Page 40)
Question
1: Give an example of a metal which
(i) is a
liquid at room temperature.
(ii) can
be easily cut with a knife.
(iii) is
the best conductor of heat.
(iv) is
a poor conductor of heat.
Answer: (i) Mercury.
(ii) Sodium. (iii) Silver. (iv) Lead and Mercury.
Question
2: Explain the meanings of malleable and ductile.
Answer:
Malleable: Some metals can be beaten into thin sheets. This
property is called malleability and such substances are called malleable. For
example gold, silver.
Ductile: Substances that can be drawn into thin wires are
called ductile. Most of the metals are ductile.
CBSE NCERT Solutions: InText Questions (Page 46)
Question
3: Why is sodium kept immersed in kerosene oil?
Answer: Sodium is highly reactive on exposure to air at
room temperature. It reacts with oxygen and catches fire. It also reacts with
water. But, it neither reacts nor dissolves in kerosene. So, in order to
protect it sodium is kept under kerosene.
Question
4: Write equations for the reactions of
(i) Iron
with steam
(ii)
Calcium and potassium with water
Answer:
Also Read: Metals and Non-Metals - NCERT Answers of Class 10 NCERT Science Chapter 3 exercise questions
Question
5: Samples of four metals A, B, C and D were taken and added to the following
solution one by one. The results obtained have been tabulated as follows:
Metal
|
Iron (II) sulphate
|
Copper (II) sulphate
|
Zinc sulphate
|
Silver nitrate
|
A
|
No reaction
|
Displacement
|
||
B
|
Displacement
|
No reaction
|
||
C
|
No reaction
|
No reaction
|
No reaction
|
Displacement
|
D
|
No reaction
|
No reaction
|
No reaction
|
No reaction
|
Use the
Table above to answer the following questions about metals A, B, C and D.
(i)
Which is the most reactive metal?
(ii)
What would you observe if B is added to a solution of Copper (II) sulphate?
(iii)
Arrange the metals A, B, C and D in the order of decreasing reactivity.
Answer: From
the above table we obtain the reactivity series as follows:
Zn > B > Fe > A > Cu > C > Ag
> D
(i) Metal B is the most reactive metal.
(ii) Displacement reaction.
(iii) Metal B > Metal A > Metal C >
Metal D.
Question
6: Which gas is produced when dilute hydrochloric acid is added to a reactive
metal? Write the chemical reaction when iron reacts with dilute H2SO4.
Answer: Hydrogen gas is evolved along with salt of the
metal. Equation for the chemical reaction that will take place between iron and
dil. H2SO4 is -
Question
7: What would you observe when zinc is added to a solution of iron(II)
sulphate? Write the chemical reaction that takes place.
Answer: Since,
zinc is more reactive than iron. So, it will displace iron from iron(II)
sulphate. The equation will be as follows:
Also Read:
CBSE NCERT Solutions: InText Questions (Page 49)
Question
8: (i) Write the electron-dot structures for sodium, oxygen and magnesium.
(ii)
Show the formation of Na2O and MgO by transfer of electrons.
(iii)
What are the ions present in these compounds?
Answer: (i)
(ii)
(iii)
Question 9: Why do Ionic compounds have high melting points?
Answer: The molecules of Ionic compounds are bounded by
strong electrostatic force of attraction between the ions. Hence, it requires a
lot of energy to overcome these forces and so Ionic compounds have high melting
and boiling points.
CBSE NCERT Solutions: InText Questions (Page 53)
Question 10: Define the following terms.
(i)
Mineral (ii) Ore (iii) Gangue
Answer: (i) Mineral - The elements or compounds which occur naturally
in the earth's crust are known as minerals.
(ii) Ore - At some places, minerals contain a very high
percentage of a particular metal and the metal can be profitably extracted from
it. These minerals are called ores.
(iii) Gangue - Ores mined from the earth are usually
contaminated with large amounts of impurities such as soil, sand, etc, called
gangue.
Question
11: Name two metals which are found in nature in the free state.
Answer: Gold, Platinum.
Question
12: What chemical process is used for obtaining a metal from its oxide?
Answer: The chemical process used for obtaining a metal
from its oxide is reduction. The metal oxides are reduced by using a suitable
reducing agent like carbon or by a more reactive metal to cause a displacement
reaction. For example,
CBSE NCERT Solutions: InText Questions (Page 55)
Question
13: Metallic oxides of zinc, magnesium and copper were heated with the
following metals.
Metal
|
Zinc
|
Magnesium
|
Copper
|
Zinc oxide
|
|||
Magnesium oxide
|
|||
Copper oxide
|
In which
cases will you find displacement reactions taking place?
Answer:
Metal
|
Zinc
|
Magnesium
|
Copper
|
Zinc oxide
|
No
|
Yes
|
No
|
Magnesium oxide
|
No
|
No
|
No
|
Copper oxide
|
Yes
|
Yes
|
No
|
Question
14: Which metals do not corrode easily?
Answer: More reactive a metal, the chances of its
corrosion is more. So, metals low in activity series, like gold, silver, etc.
do not corrode easily.
Question
15: What are alloys?
Answer: An alloy is a homogenous mixture of two or more
metals, or a metal and a non-metal.
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