# Identify the correct order of boiling points of the following compounds : $CH_3 CH_2 CH_2OH,CH_3CH_{\large 2_2}CH_2CHO , CH_3CH_{\large 2_3}CH_2COOH$

$(a)\; 1 > 2 > 3 \\ (b)\; 3 > 1 > 2 \\ (c)\; 1 > 3 > 2 \\ (d)\; 3 > 2 > 1$

Higher the molecular weight will be the boiling points.
So, $CH_3 CH_2CH_2COOH > CH_3CH_2CH_2CH_2OH > CH_3CH_2CH_2CHO$ (ie) $3 > 2 > 1$
Carboxylic acid shows strongest inter molecular H- bonding and aldehyde shows weakest H-bond.
Hence d is the correct answer.
answered Feb 21, 2014 by 1 flag

3>1>2. Generally three factors affect boiling point. 1.hydrogen bonding 2. Dipole moment 3. Molecular weight. Ch3Ch2Ch2CooH will have greatest BP due to H bonding and more molecular weight. Then alcohol due to H bonding and then aldehyde. Hope it helps!