An aliphatic aldehyde contains only one $O$ atom and no multiple bond. This aldehyde undergoes complete combustion. 1) Write the combustion équation! 2) Since the combustion of one mole provides $67.2\;L$ $CO_2$ NTP, identify this aldehyde!
1) $C_xH_{2x}O$ $+$ $\frac{3x-1}{2}O_2$ $\rightarrow$ $x CO_2$ $+$ $xH_2O$ 2) $n(CO_2)$ $=$ $\frac{67.2}{22.4}$ $=$ $3$ so $x$ $=$ $3$ Molecular formula: $C_3H_6O$ Semi-structural formula: $CH_3CH_2CHO$ Name: propanal
