EVERYDAY SCIENCE

Detailed explanation-1: -Carbon dioxide is released during the exhalation of air from the lungs. The partial pressure of carbon dioxide gas in exhaled air is high. When exhaled air is blown into a test tube containing lime water, it is converted into limestone. Limewater becomes milky in the presence of carbon dioxide.

Detailed explanation-2: -Limewater as Indicator of Carbon Dioxide Gas. Description: Carbon dioxide gas from a cylinder is bubbled through limewater and calcium carbonate solid is formed causing the limewater to become cloudy.

Detailed explanation-3: -Limewater is a solution of calcium hydroxide. If carbon dioxide is bubbled through limewater, the limewater turns milky or cloudy white.

Detailed explanation-4: -Lime water reacts with carbon dioxide during respiration, forming calcium carbonate (CaCO3). This makes lime water milky. It is a colourless and odourless gas.

Detailed explanation-5: -Carbon dioxide reacts with lime water to form calcium carbonate as the white precipitate. Thus, the second lime water test tube turns milky first.