Question

Match the following reactions with the corresponding reagents} Reactions \hspace{3cm} Reagents} (a) Oxidation of secondary alcohols to ketones \hspace{0.3cm} (i) $85%\,H_3PO_4,\ 440K$} (b) Dehydration of secondary alcohols to alkenes \hspace{0.1cm} (ii) $Na_2Cr_2O_7/H_2SO_4$} (c) Reduction of ketones to secondary alcohols \hspace{0.5cm} (iii) Chromic anhydride} (d) Oxidation of phenol to benzoquinone \hspace{0.2cm} (iv) $NaBH_4$

• A. (a)-(iii), (b)-(iv), (c)-(i), (d)-(ii)
• B. (a)-(iii), (b)-(i), (c)-(iv), (d)-(ii)
• C. (a)-(iii), (b)-(ii), (c)-(i), (d)-(iv)
• D. (a)-(i), (b)-(iv), (c)-(ii), (d)-(iii)
• E. (a)-(iv), (b)-(i), (c)-(iii), (d)-(ii)

Hint:

$NaBH_4$ is a mild reducing agent commonly used to convert aldehydes and ketones into alcohols.

Answer 1

The Correct Option is B

Concept:
Organic reactions are identified from standard reagents and their known actions.
Step 1: Match oxidation of secondary alcohol.
Secondary alcohols are oxidized to ketones by chromic anhydride. \[ (a)\rightarrow(iii) \]
Step 2: Match dehydration reaction.
Secondary alcohols give alkenes on dehydration using phosphoric acid at high temperature. \[ (b)\rightarrow(i) \]
Step 3: Match reduction of ketone.
Ketones are reduced to secondary alcohols by sodium borohydride. \[ (c)\rightarrow(iv) \]
Step 4: Match oxidation of phenol.
Phenol is oxidized to benzoquinone using acidified sodium dichromate. \[ (d)\rightarrow(ii) \]
Step 5: Final matching.
\[ (a)-(iii),\ (b)-(i),\ (c)-(iv),\ (d)-(ii) \]
Hence, correct option is (B).