Diborane is completely hydrolysed: $B X_{2} H X_{6} + 6 H X_{2} O 2 H X_{3} BO X_{3} + 6 H X_{2}$ . Taking atomic masses B = 11 and H = 1 and molar volume 22.4 L/mol at STP, find the volume of hydrogen (in litres at STP, two decimals) liberated from 5.6 g of $B X_{2} H X_{6}$ .

Numerical answer type, answer in L, tolerance 0.01.

Answer: 26.88 L

Molar mass of

B X_{2} H X_{6}

= 2(11) + 6(1) = 28 g/mol, so moles = 5.6/28 = 0.20 mol. Each mole gives 6 mol

H X_{2}

, so

H X_{2}

= 1.20 mol. Volume = 1.20 x 22.4 = 26.88 L.