11. What volume of \( O _{2} \) gas is liberated at STP on heating \( 24.5 g \) of \( KClO _{3}\left[\right. \) Molar mass of \( KClO _{3}=122.5 g / mol \) ] a) \( 6 dm ^{3} \) b) \( 12 dm ^{3} \) c) \( 3 dm ^{3} \) d) \( 1.5 dm ^{3} \)