Question

An experiment was conducted in a class where students were asked to blow air into a

test tube containing lime water with the help of a straw. The observation of the

experiment is shown in the image. What turns the lime water milky?

(a) Reaction of oxygen gas present in the exhaled air with the lime water.

(b) Reaction of all gases present in the atmosphere with the lime water.

(c) Reaction of nitrogen gas present in the atmosphere with the lime water.

(d) Reaction of carbon dioxide gas present in the exhaled air with the lime

water...... plz answer in text and dont send photos of the answer​

Answer 1

(d) Reaction of carbon dioxide gas present in the exhaled air with the lime water is the correct answer.

1. Humans exhale mixture of gases which contains carbon dioxide as well. Exhaled air has 100 fold increase in carbon dioxide amount with respect to inhaled carbon dioxide.
2. Lime water is chemically a solution of calcium hydroxide. Calcium hydroxide reacts with carbon dioxide in exhaled air, yielding products calcium carbonate and hydrogen gas.
3. The calcium carbonate precipitates turning lime water milky.