SATHEE: Alkyl Halides - Result Question 14

Alkyl Halides - Result Question 14

####14. The increasing order of reactivity of the following halides for the $S_{N} 1$ reaction is

(2017 Main)

I. $C H_{3} C H (C l) C H_{2} C H_{3}$

II. $C H_{3} C H_{2} C H_{2} C l$

III. $p - H_{3} C O - C_{6} H_{4} - C H_{2} C l$

(a) (III) $<$ (II) $<$ (I)

(b) (II) $<$ (I) $<$ (III)

(d) (II) $<$ (III) $<$ (I)

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Answer:

Correct Answer: 14. (b)

Solution:

(i) The rate of $S_{N} 1$ reaction depends only upon the concentration of the alkyl halide.

(ii) $S_{N} 1$ reaction proceeds through the formation of carbocation.

The reactivity is decided by ease of dissociation of alkyl halide.

$R - X ⇌ R^{\oplus} + X^{Θ}$

Higher the stability of $R^{+}$ (carbocation), higher would be the reactivity towards $S_{N} 1$ reaction.

$p - H_{3} C O - C_{6} H_{4} - C H_{2}^{\oplus}$ is the most stable carbocation due to resonance and then $C H_{3} \underset{\oplus}{C H C H_{2}} C H_{3}$ (2 $2^{\circ}$ carbocation) while $C H_{3} C H_{2} C H_{2} (1^{\circ})$ is least stable.

Thus, the correct increasing order of the reactivity of the given halides towards the $S_{N} 1$ reaction is

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Alkyl Halides - Result Question 14

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Alkyl Halides - Result Question 14

Answer:

Engineering Preparation

Medical Preparation

NCERT Books & Solutions

Important Resources

Other Resources

Syllabus

Test Platform

Sample Mock Test

Mentorship

NCERT Exercise Video Solution

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