Question

Which of the following woud you expect to have a higher boiling point? Why?

1. CH4 or HF

2. CH3OCH3 CH3CH2OH

3. CH4 of C2H6

4. CH4 or SiH4

Answer 1

Case 1) Methane is gas and boils at -161 °C and HF boiling point is 19.5 °C. Due strong intra molecular hydrogen bondings of HF, HF has higher boining point compare to methane.

Case 2) Di ethyl ether has less boing point (34 °C) as compare to ethanol (64 °C), due to same reason as above of intra molecular hydrogen bonding.

Case 3) Methane is gas at room temperature as discussed earlier and boils at -161°C, benzene is liquid and boils at 80 °C. Due to Pi bond attraction within the molecules make it higher boing as compare to methane.

Case 4) Here Metane and Silane (-112 °) and both volatile, but silane is more polar character as compare to methane and due to its high molecular weight it has higher boiling point as compare to methane.