These are some PYQs (previous year questions) from the CBSE board for Class 10 Science, Chapter 3: Metals and Non-metals.
By practicing these questions, you will get an idea of what type of questions may appear in the examination.
Question 1:
A metal and a non-metal that exists in liquid state at room temperature are respectively:
(a) Bromine and Mercury
(b) Mercury and lodine
(c) Mercury and Bromine
(d) lodine and Mercury
1 mark; CBSE 2024
Answer:
(c) Mercury and Bromine
Question 2:
Four solutions, namely glucose, alcohol, hydrochloric acid and sulphuric acid filled in four separate beakers are connected one by one in an electric circuit with a bulb. The solutions in which the bulb will glow when current is passed are:
(a) Glucose and alcohol
(b) Alcohol and hydrochloric acid
(c) Glucose and sulphuric acid
(d) Hydrochloric acid and sulphuric acid
1 mark; CBSE 2024
Answer:
(d) Hydrochloric acid and sulphuric acid
Question 3:
Name a metal/non-metal
a. Which makes iron hard and strong?
b. Which is alloyed with other metal to make amalgam?
c. Which is used to galvanise iron articles?
d. Whose articles when exposed to air forms a black coating?
2 mark; CBSE 2016
Answer:
a. Carbon and tungsten both make materials hard and strong.
b. Mercury is mixed with metals to create an amalgam.
c. Zinc is used to coat iron to prevent it from rusting.
d. Silver items turn black when exposed to the air.
Question 4:
Write one example of each of
a. a metal which is so soft, that it can be cut with a knife and a non-metal which is the hardest known substance.
b. a metal and a non-metal which exist as liquid at room temperature.
2 mark; CBSE 2015
Answer:
a. Sodium is very soft and can be cut with a knife. In contrast, diamond, an allotrope of carbon, is the hardest known substance and is a non-metal.
b. Mercury and bromine are unique because they are both in liquid form at room temperature, with mercury being a metal and bromine a non-metal.
Question 5:
Give reason for the following:
a. School bells are made up of metals.
b. Electrical wires are made up of copper.
2 mark; CBSE 2014, 2013
Answer:
a. Metals are sonorous, meaning they make a sound when hit with a hard object.
b. Copper is a great conductor of electricity and is very flexible.
Question 6:
In one of the methods of rust prevention, iron is not coated with anything. Name that method and define it.
2 mark; CBSE 2014
Answer:
The method involves creating an alloy by adding a suitable metal or non-metal. An alloy is a uniform mixture of two or more metals, and sometimes a non-metal can be included. This process is known as alloying.
Question 7:
Name the following:
a. A metal which is preserved in kerosene.
b. A lustrous coloured non-metal.
c. A metal which melts when kept on palm.
d. A metal which is a poor conductor of heat.
2 mark; CBSE 2013, 2012
Answer:
a. Sodium or Potassium
b. Iodine
c. Gallium
d. Lead
Question 8:
X + YSO4 –> XSO4 + Y
Y + XSO4 –> No reaction
Out of the two elements, X and Y, which is more reactive and why?
2 mark; CBSE 2011
Answer:
X is more reactive than Y because it is displacing Y from its salt solution.
Question 9:
Write a balanced chemical equation for representing the chemical reaction between manganese dioxide and aluminium powder. What happens if manganese powder is heated with aluminium oxide?
2 mark; CBSE 2010
Answer:
3MnO2 + 4Al –> 2Al2O3 + 3Mn
No reaction will take place if manganese powder is heated with Al2O3 because Mn is less reactive than Al.
Question 10:
Explain the following statements:
a. Most metal oxides are insoluble in water but some of these dissolve in water. What are these oxides and their solution in water called?
b. At ordinary temperature the surface of metals such as magnesium, aluminium, zinc etc. is covered with a thin layer. What is the composition of this layer? State its importance.
c. Some alkali metals can be cut with knife.
3 mark; CBSE 2016
Answer:
a. These oxides are basic, and their solutions are called alkalies.
b. This layer is made of metal oxide and protects the metal from corrosion.
c. Sodium is a very soft metal, so it can be cut with a knife.
Question 11:
Distinguish between the following:
a. Electrolytic reduction and electrolytic refining.
b. Mineral and ore.
c. Alloys and amalgams
3 mark; CBSE 2015
Answer:
| Electrolytic reduction | Electrolytic refining |
| Metal is obtained by electrolysis of molten ore. | Metal is refined by taking impure metal as anode, pure metal as cathode and soluble salt of metal as electrolyte and by passing electric current. |
| Mineral | Ore |
| Naturally occurring substances from which metal may or may not be extracted economically e.g., Mica. | Naturally occurring substances from which metal is extracted profitably e.g., Bauxite is an ore of Al. |
| Alloys | Amalgams |
| Homogeneous mixture of two or more metals. One of them can be a nonmetal also e.g., steel. | Homogenous mixture of mercury with any other metals e.g., zinc amalagam. |
Question 12:
a. Define corrosion.
b. What is corrosion of iron called?
c. How will you recognise the phenomena of corrosion of silver?
d. Why corrosion of iron metal is a serious problem?
e. How can we prevent corrosion of iron?
5 mark; CBSE 2016
Answer:
a. Corrosion happens when a metal reacts with substances in the air and forms surface compounds.
b. When iron corrodes, it’s called rusting.
c. Silver turns black when it corrodes because it forms silver sulfide (Ag2S).
d. Corrosion weakens structures like bridges and wastes a lot of iron each year.
e. To prevent iron from corroding, you can:
– Paint it,
– Oil and grease it,
– Galvanize it, or
– Use iron alloys.
