Q1: Lead acetate test in sewer manhole is done to test the presence of

ANS:B - Hydrogen sulphide

The lead acetate test conducted in a sewer manhole is done to test the presence of hydrogen sulfide gas. Hydrogen sulfide (H2S) is a colorless, highly toxic gas that is commonly found in sewer systems as a byproduct of anaerobic bacterial decomposition of organic matter containing sulfur compounds. It is responsible for the characteristic foul odor often associated with sewers and wastewater treatment facilities. The lead acetate test involves using lead acetate paper or strips, which react with hydrogen sulfide gas to form lead sulfide, a black precipitate. By placing lead acetate paper near potential sources of hydrogen sulfide, such as sewer manholes, the presence of the gas can be detected based on the formation of the black precipitate on the paper. Detecting the presence of hydrogen sulfide is important for assessing the safety and environmental conditions within sewer systems and for implementing appropriate measures to control odor and mitigate health risks associated with exposure to the gas.