Question

Which one among the following compounds will most readily be dehydrated under acidic condition?
 

(A)	(B)	(C)	(D)
CH3-CH2-CH2-OH	CH3-CH(CH3)-CH2-OH	CH3-CH2-CH(CH3)-OH	C(CH3)(CH3)-CH2-OH
(1° alcohol)	(2° alcohol)	(2° alcohol)	(3° alcohol)

• A. A
• B. B
• C. C
• D. D

Hint:

Tip about dehydration of alcohols Key Points:
Protonation of -OH creates better leaving group (H$_2$O)
Carbocation stability determines rate: \chemfig{C^+(-[::+60]R)(-[:-60]R)-R>\chemfig{R-CH^+-R>\chemfig{R-CH_2^+
Rearrangements possible for less stable carbocations

Answer 1

The Correct Option is D

Acid-catalyzed alcohol dehydration favors carbocation stability: \(3^\circ>2^\circ>1^\circ\).
\r\n
\(A) Primary alcohol (slowest)
\r\n
(B) Secondary alcohol
\r\n
(C) Secondary alcohol
\r\n
(D) Tertiary alcohol (fastest)
\r\n
Tertiary alcohol (D) dehydrates fastest due to the formation of the most stable carbocation intermediate.