5. 20
11. 20
2. 24
20. 20
6. 20
Correct answer is B
P4 + 502 → P4O10
for the complete combustion of 124 grammes of phosphorus we need
5 x 22.4 litres of O2
for 12.4 gms of P4 we need
\(\frac{5 \times 22.4}{124} \times \frac{12.4}{1}\)
\(\frac{22.4}{2}\) = 11.2 litres