• # question_answer 1 L of a gas at S.T.P. weighs 1.97 g. What is the vapour density of the gas?

22.4 L of the gas at S.T.P. will weigh =$1.97\times 22.4\,g$= 44.1 g , i.e., molecular mass = 44.1. Hence, vapour density = 44.1/2 = 22.05.