Answer: B (\(2\text{C}_4\text{H}_{10} + 13\text{O}_2 \rightarrow 8\text{CO}_2 + 10\text{H}_2\text{O}\)). In complete combustion every carbon becomes \(\text{CO}_2\) and every two hydrogens become \(\text{H}_2\text{O}\).
Taking \(2\text{C}_4\text{H}_{10}\): 8 carbons give \(8\text{CO}_2\) and 20 hydrogens give \(10\text{H}_2\text{O}\). The oxygen needed is \(8 \times 2 + 10 = 26\) oxygen atoms, which is \(13\text{O}_2\). This gives option B.
A has 5 carbons on the right (butane has 4), C lists \(\text{H}_2\) as a product, and D has inconsistent carbon and oxygen counts. Answer B.
Every O Level Pure Chemistry TYS MCQ solution video, plus full Sec 3 / Sec 4 topic recordings.
Find out more