$*)\begin{cases}X:C_{n}H_{2n}:x mol \\Y:C_{2n}H_{4n-2}:y mol \end{cases}\Rightarrow 14nx+(28n-2)y=2,18 (1)$$*)n_{H_2O}=nx+(2n-1)y=\frac{2,34}{18}=0,13 mol (2)$
$*)\begin{cases}(1) \\ (2) \end{cases}\Rightarrow y=0,03 mol\Rightarrow 0,03.(2n-1)<0,13\Rightarrow n<2,6667\Rightarrow n=2$
$\Rightarrow \begin{cases}CH_2=CH_2:x mol \\ CH_2=CH-CH=CH_2:y=0,03 mol \end{cases}\Rightarrow \begin{cases}x=0,02 mol \\ y=0,03 mol \end{cases}$
$a)\Rightarrow n_{CO_2}=nx+2ny=0,16 mol\Rightarrow n_{O_2}=n_{CO_2}+0,5n_{H_2O}=0,225 mol$
$b)\begin{cases}CH_2=CH_2:0,02 mol \\ CH_2=CH-CH=CH_2:0,03 mol \end{cases}\Rightarrow \begin{cases}\%V_X=40\% \\ \%V_Y=60\% \end{cases}$