1120 mL of CI2 gas at N.T.P. weighs 3.55 g. Find the atomic weight of chlorine.

1120 mL weighs 3.55 g. So, 22400 mL weighs(3.55/1120) x 22400 = 71 g mol. wt. But mol. wt.= Atomicity of Cl2 x at. wt.So, 71 = 2 x at. wt. Thus, at. wt. = 35.5