When air is blown from mouth into a test tube containing limewater, the limewater turns milky. This is due to the presence of

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

What is the colour of the precipitate obtained by passing CO₂ gas through lime water?

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

Silver articles turn black when kept in the open for longer time due to the formation of

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?