32 g of SO2 and 12 g of O2 react as far as possible in 2SO2 + O2 -> 2SO3 (S=32, O=16). Find the mass in grams of the reactant left over, to one decimal place.

JEE Main levelNumerical answerDifficulty 2 of 3mc065

$32 g$ of $SO X_{2}$ and $12 g$ of $O X_{2}$ react as far as possible in $2 SO X_{2} + O X_{2} 2 SO X_{3}$ ( $S = 32$ , $O = 16$ ). Find the mass in grams of the reactant left over, to one decimal place.

Numerical answer type, answer in g, tolerance 0.05.

SO X_{2}

= 0.5 mol,

O X_{2}

= 0.375 mol.

SO X_{2}

requires only 0.25 mol

O X_{2}

, so

SO X_{2}

is limiting and is consumed fully.

O X_{2}

left = 0.375 - 0.25 = 0.125 mol = 4.0 g.