Question

ii) The ratio of nitrogen to oxygen in the air is
a) 1:4
b) 4:1
c) 3:1
d) 1:2

iii) The gas present in the air which turns limewater milky is

a) Oxygen

b) Nitrogen

c) Argon
d) Carbon dioxide
iv) The oxygen present in the air is used for
a) respiration
b) burning
c) extinguish fire
d) both (a) and (b).
v) Air is used for
a) separating husk from grains
b) flying birds
c) dispersal of seeds
d) all of these.

Answer 1

Answer:

When carbon dioxide is passed through lime water for a short time,it turns lime water milky due to formation of a white precipitate of calcium carbonate.

Exhaled air contains less oxygen and more carbon dioxide.

The carbon dioxide present in exhaled air turns lime water milky.

So the correct answer is 'Carbon dioxide'.

Explanation: