Correct Answer - A
Let the mass of gaseous hydrocarbon taken = w gm
`:. %C = (12)/(44) xx (3.08)/(w) xx 100 = (84)/(w)`
`%H = (2)/(18) xx (0.72)/(w) xx 100 = (8)/(w)`
Ratio of C : H atoms `= (84)/(w) xx(1)/(12) : (8)/(w) xx (1)/(1) = 7 : 8`
Thus, E.F. = `C_(7)H_(8)`.