Question

If the reaction of 4.50 moles of sodium with excess hydrofluoric acid produced an 85.0% yield of hydrogen gas, what was the actual yield of hydrogen gas?

Unbalanced equation: Na + HF NaF + H2

1.91 mol H2

2.25 mol H2

2.65 mol H2

3.82 mol H2

Answer 1

\[2 Na + 2 HF \rightarrow 2NaF + H_2\]
thus:
\[ \frac{ 4.5 }{ 2 }\times 0.85\] = moles of H2