What mass of KClO3 must be decomposed by 2KClO3 -> 2KCl + 3O2 to obtain 6.72 L of O2 at STP? (K=39, Cl=35.5, O=16)

JEE Main levelSingle correct optionDifficulty 2 of 3mc131

What mass of $KClO X_{3}$ must be decomposed by $2 KClO X_{3} 2 KCl + 3 O X_{2}$ to obtain 6.72 L of $O X_{2}$ at STP? ( $K = 39$ , $Cl = 35.5$ , $O = 16$ )

Moles of

O X_{2}

= 6.72/22.4 = 0.3. Moles of

KClO X_{3}

= 0.3 x 2/3 = 0.2. Molar mass = 39 + 35.5 + 48 = 122.5. Mass = 0.2 x 122.5 = 24.5 g.