Question

What volume of `H_(2)` at `273 K` and 1 atm will be consumed in obtaining `21.6 g` of elemental boron (atomic mass of `B = 10.8)` from the reduction of `BCl_(3)` with `H_(2)`.
A. `89.6 L`
B. `67.2 L`
C. `44.8 L`
D. `22.4 L`

Answer 1

Correct Answer - B
`2BCl_(3) + 3H_(2) rarr 2B + 6HCl`
`2 xx 10.8 g B -= 3 xx 22.4 L` of `H_(2)`
`21.6 g B -= (3 xx 22.4 xx 21.6)/(2 xx 10.8) = 67.2 L` of `H_(2)`