On polar stratospheric clouds, 0.35 mol of ClONO2 reacts completely with excess HCl (ClONO2 + HCl -> Cl2 + HNO3), and in spring all the Cl2 formed is photolysed to Cl atoms. The amount of Cl atoms formed (in mol) is

JEE Advanced levelSingle correct optionDifficulty 3 of 3ev098

On polar stratospheric clouds, 0.35 mol of $ClONO X_{2}$ reacts completely with excess $HCl$ ( $ClONO X_{2} + HCl Cl X_{2} + HNO X_{3}$ ), and in spring all the $Cl X_{2}$ formed is photolysed to Cl atoms. The amount of Cl atoms formed (in mol) is

One mole of ClONO2 gives one mole of

Cl X_{2}

, so 0.35 mol of

Cl X_{2}

is formed. Each

Cl X_{2}

gives two Cl atoms on photolysis: 0.35 x 2 = 0.7 mol of Cl atoms. (Note that this chlorine came from both ClONO2 and HCl.)