When we heat lead nitrate [P(NO₃)₂] in a boiling tube, we observe the emission of brown fumes. Which one of the following is the brown gas?

Which one of the following materials is present in a guard tube (drying tube) that is used for preparation of HCl gas?

A liquid is heated up to a certain temperature. Which one of the following situation would correspond to the boiling of the liquid?

Which one of the following is not an oxidation reaction?

An iron nail dipped in copper sulphate solution turns brown. This is due to which one of the following types of reactions?

Which one of the following is not an example of an oxidation reaction?