Question

Fill in the blanks in the following statements:
(a) When carbon dioxide is passed through lime water, it turns milky due to the formation of _________.
(b) The chemical name of baking soda is _________.
(c) Two methods by which rusting of iron can be prevented are _________ and _________.
(d) Changes in which only _________ properties of a substance change are called physical changes.
(e) Changes in which new substances are formed are called _________ changes.
NCERT Solutions for Class 7th Science Chapter 6 Physical and Chemical Changes Page 66 Exercise Question 3

Answer 1

a. Calcium Carbonate (CaCO3)
b. Sodium Hydrogen Carbonate or Sodium Bicarbonate
c. by applying paint or grease and by the coating of zinc which is called Galvanisation.
d. physical
e. chemical.

Answer 2

A) CO2 reacts with calcium carbonate. B) Sodium bicarbonate. C) 1.keeping away from moisture 2.paint the metallic surface D) Physical E) chemical changes