SATHEE: Hydrocarbons - Result Question 55

Hydrocarbons - Result Question 55

####57. Base strength of :

[2008] (A) $H_{3} C - C H_{2}$ (B) $H_{2} C = C H$ and (C) $H - C \equiv \overset{―}{C}$

is in the order of :

(a) (B) $>$ (A) $>$ (C)

(b) $($ C $) >$ (B) $>$ (A)

(d) (A) $>$ (B) $>$ (C)

Show Answer

Solution:

(d) The amount of s-character in various hybrid orbitals is as follows.

$s p = 50$ and $s p^{3} = 25$

Therefore $s$ -character of the $C - H$ bond in acetylene $(s p)$ is greater than that of the $C - H$ bond in alkene ( $s p^{2}$ hybridized) which in turn has greater $s$ -character of the $C - H$ bond in alkanes. Thus, owing to a high $s$ -character of the $C - H$ bond in alkynes, the electrons constituting this bond are more strongly held by the carbon nucleus with the result the hydrogen present on such a carbon atom can be easily removed as proton. The acidic nature of three types of $C - H$ bonds follows the following order

$\equiv C - H >= C - H > - C - H$

Further, as we know that conjugate base of a strong acid is a weak base, hence the correct order of basicity is

$H - C \equiv \overset{(-)}{C} < C H_{2} = \overset{(-)}{C} H < \overset{(-)}{C H_{2}} - C H_{3}$

Hydrocarbons - Result Question 55

Solution:

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Hydrocarbons - Result Question 55

Solution:

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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