Question

How many moles of oxygen gas are needed to perform the combustion of one mole of alkane, `C_(n)H_(2n+1)`?
A. `3n`
B. `3n+1`
C. `n+1`
D. `((3n+1))/(2)`

Answer 1

Correct Answer - D
The number of moles of `CO_(2)` is always equal to the number of moles of `C` because one `C` gives one `CO_(2)`. The number of moles of `H_(2)O` is half of the number of moles of `H` because on `H` gives `1//2H_(2)O`.
`nCrarrnCO_(2), i.e.,nO_(2)`
`2(n+1)Hrarr(n+1)H_(2)O, i.e, (n+1)/(2)O_(2)`