The correct answer is: B. Hydrogen sulphide
Lead acetate test is a simple test that can be used to detect the presence of hydrogen sulfide gas. The test is performed by adding a few drops of lead acetate solution to a sample of the gas. If hydrogen sulfide is present, a black precipitate will form.
Hydrogen sulfide is a colorless, flammable gas with a rotten egg odor. It is produced by the decomposition of organic matter in the absence of oxygen. Hydrogen sulfide is toxic and can cause a variety of health problems, including respiratory problems, nausea, vomiting, and death.
Methane gas is a colorless, odorless, and flammable gas. It is produced by the decomposition of organic matter in the presence of oxygen. Methane is not toxic, but it can be explosive in high concentrations.
Carbon dioxide gas is a colorless, odorless, and non-flammable gas. It is produced by the respiration of animals and the decomposition of organic matter. Carbon dioxide is not toxic, but it can cause asphyxiation in high concentrations.
Diesel vapours are a mixture of hydrocarbons that are produced when diesel fuel is burned. Diesel vapours are flammable and can cause explosions.
Therefore, the lead acetate test is done to test the presence of hydrogen sulfide gas.