Question

Which of the given statement is not correct

• A. Phenol is more acidic than acetic acid
• B. Ethanol is less acidic than phenol
• C. Ethanol has higher boiling point than ethane
• D. Ethyne is a linear molecule

Answer 1

Answer: (A)

Phenols are much more acidic than alcohols but less acidic than carboxylic acids (acetic acid) or even carbonic acid. This is indicated by the values of ionisation constants. The relative acidity follows the order:
$K_a\underset{RCOOH}{10^{-5}}>\underset{H_{2}C{O}_3}{10^{-7}}>\underset{C_6{H}_{5}OH}{10^{-10}}>\underset{HOH}{10^{-14}}>\underset{ROH}{10^{-18}}$
Ethanol has higher boiling point than ethane due to hydrogen bonding.
Ethyne is a linear molecule because it has sp hybridised carbon atoms.