Multiple Choice

Which of the following is/are correct?

A$$PhOH$$ has a higher boiling point than $$PhSH$$ (benzenthiol).
Correct Answer
B$$p-Hydroquinone$$ has a higher melting point than catechol.
Correct Answer
C$$o-Nitrophenol$$ has a lower boiling point than $$m-$$ and $$p-isomers$$.
Correct Answer
D$$o-Hydroxybenzaldehyde$$ is more water soluble than $$m-$$ and $$p-isomers$$.

Solution

$$a.$$ $$PhOH$$ has higher boiling point due to $$H-bonding$$.
$$b.$$ Molecules of $$p-benzonoquinone$$ can fit closer in solid state causing it to have higher melting point.
$$c. and \,d.$$ Intramolecular H-bonding (chelation) in the o-isomers inhibits the intermolecular attraction, lowers the boiling point, reduces H-bonding with $$H_2O$$, and decreases water solubilities. Intra-molecular chelation dots not occur in m- and $$p-isomers$$.

Hence, Options "A" ,"B" & "C" are correct answers.

SIMILAR QUESTIONS

Organic Compounds Containing Nitrogen

The correct order of boiling points of the following isomeric amines is: $$C_4H_9NH_2.(C_2H_5)_2NH,\, C_2H_5N(CH_3)_2$$

Organic Compounds Containing Nitrogen

The decreasing order of boiling points of ethyldimethylamine, n- butylamine and diethylamine is n - Butylamine > Diethylamine > Ethyldimethylamine. This trend of the boiling point can be explained as:

Organic Compounds Containing Nitrogen

Give plausible explanation for each of the following: (i) Why are amines less acidic than alcohols of comparable molecular masses? (ii) Why do primary amines have higher boiling point than tertiary amines? (iii) Why are aliphatic amines stronger bases than aromatic amines?

Organic Compounds Containing Nitrogen

The correct order of boiling points of the following isomeric amines is: $$C_4H_9NH_2.(C_2H_5)_2NH,\, C_2H_5N(CH_3)_2$$

Organic Compounds Containing Nitrogen

The decreasing order of boiling points of ethyldimethylamine, n- butylamine and diethylamine is n - Butylamine > Diethylamine > Ethyldimethylamine. This trend of the boiling point can be explained as:

Organic Compounds Containing Nitrogen

Tertiary amines have lowest boiling points amongst isomeric amines because:

Organic Compounds Containing Nitrogen

Give plausible explanation for: Why do primary amines have higher boiling points than tertiary amines?

Organic Compounds Containing Nitrogen

Give reasons for the following: Primary amines have higher boiling point than tertiary amines.

Organic Compounds Containing Nitrogen

Account for the following: Although trimethylamine and n-propylamine have the same molecular weight, but the former boils at a lower temperature (276K) than the latter (322K). Explain why.

Organic Compounds Containing Nitrogen

Which of the following compounds has the lowest boiling point?

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