JEE Main · 2021 · 27 Jul 2021 · Shift 2 · Compounds Containing Nitrogen

The correct sequence of correct reagent for the following transformation is:

(A)(i) $Cl_{2}, FeCl_{3}$
(ii) $NaNO_{2}, HCl, 0^{\circ} C$
(iii) $Fe, HCl$
(iv) $H_{2} O / H^{+}$
(B)(i) $Cl_{2}, FeCl_{3}$
(ii) $Fe, HCl$
(iii) $NaNO_{2}, HCl, 0^{\circ} C$
(iv) $H_{2} O / H^{+}$ ✓ Correct
(C)(i) $Fe, HCl$
(ii) $Cl_{2}, HCl$
(iii) $NaNO_{2}, HCl, 0^{\circ} C$
(iv) $H_{2} O / H^{+}$
(D)(i) $Fe, HCl$
(ii) $NaNO_{2}, HCl, 0^{\circ} C$
(iii) $H_{2} O / H^{+}$
(iv) $Cl_{2}, FeCl_{3}$

Answer: (B)

Solution

In the product the chlorine sits meta to the hydroxyl group, so it must be introduced while the meta-directing nitro group is still on the ring. Chlorination with

C l_{2} /FeC l_{3}

therefore comes first and gives 3-chloronitrobenzene. Fe/HCl then reduces the nitro group to an amine,

NaN O_{2} /HCl

0^{\circ} C

converts that amine to the arenediazonium salt, and warming with

H_{2} O/ H^{+}

replaces the diazonium group by a hydroxyl group. The required sequence is

C l_{2}

FeC l_{3}

; then Fe, HCl; then

NaN O_{2}

, HCl at

0^{\circ} C

; then

H_{2} O/ H^{+}

JEE Main · 2021 · 27 Jul 2021 · Shift 2 · Single correct option

Practise more: all JEE Main PYQs on Compounds Containing Nitrogen →

JEE Main · 2021 · 27 Jul 2021 · Shift 2 · Compounds Containing Nitrogen

Solution

More JEE Main questions on Compounds Containing Nitrogen