Ortho-Nitrophenol is less soluble in water than $\mathrm{p}-$ and $\mathrm{m}-$ Nitrophenols because :

(B) o-Nitrophenol shows Intramolecular H-bonding

(A) o-Nitrophenol is more volatile in steam than those of m-and p-isomers

(C) o-Nitrophenol shows Intermolecular H -bonding

(D) Melting point of o-Nitrophenol is lower than those of m-and p-isomers.

JEE Main · 2012 · 29 Apr 2012 · Offline · Alcohols Phenols and Ethers

Ortho-Nitrophenol is less soluble in water than

p -

and

m -

Nitrophenols because :

(A)o-Nitrophenol is more volatile in steam than those of m-and p-isomers
(B)o-Nitrophenol shows Intramolecular H-bonding✓ Correct
(C)o-Nitrophenol shows Intermolecular H -bonding
(D)Melting point of o-Nitrophenol is lower than those of m-and p-isomers.

Answer: (B)

Solution

In the ortho isomer the

- OH

and

- N O_{2}

groups sit side by side, close enough for the phenolic hydrogen to bond to an oxygen of the nitro group within the same molecule. This intramolecular hydrogen bonding ties up the

- OH

so it is no longer free to hydrogen-bond to water, which lowers the solubility. The meta and para isomers cannot form such an internal bond and instead hydrogen-bond to water, so they dissolve more readily.

JEE Main · 2012 · 29 Apr 2012 · Offline · Single correct option

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JEE Main · 2012 · 29 Apr 2012 · Offline · Alcohols Phenols and Ethers

Solution

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