Question

Choose the correct option regarding $A$ and $B$.
$CH _{2}= CH _{2}+ H _{2} O +[ O ] \xrightarrow[273\, K ]{\text { Dil. } KMnO _{4}} A$
$CH _{3}- CH = CH _{2}+ H _{2} O +[ O ] \xrightarrow[273\, K ]{\text { Dil. } KMnO _{4}}B$

• A. $(A)-CH _{2}( OH )- CH _{3}, (B)-CH _{3} CH _{2} CH _{2} OH$
• B. $(A)-CH _{3} CH _{2} OH, (B)-CH _{3} CHOHCH _{3}$
• C. $(A)-CH _{3} CH ( OH ) CH _{3}, (B)-CH _{3} CH ( OH ) CH _{2} OH$
• D. $(A)-CH _{2}( OH ) CH _{2}( OH ), (B)-CH _{3} CH ( OH ) CH _{2} OH$

Answer 1

Answer: (D)

Alkenes on reaction with cold, dilute, aqueous solution of potassium permanganate (Baeyer's reagent) produce vicinal glycols. Decolorisation of $KMnO _{4}$ solution is used as a test for unsaturation.