Question

Degree of unsaturation present in compound $(A+B+C)$ is:

• A. $A+B+C=15$
• B. $A+B+C=17$
• C. $A+B+C=18$
• D. none of these

Answer 1

Answer: (B)

$A+B+C=17$

Solution:- (B) $A+B+C=17$

Reaction $1$:-

$C_6{H}_5-CHO\underset{\left(2\right){H_{3}O}^{+},\Delta }{\overset{\left(1\right){Ac}_{2}O,AcONa,\Delta }{\to }}{C}_6{H}_5-CH=CH-\stackrel{\underset{||}{O}}{C}-OH\Rightarrow$ Degree of unsaturation $=6$

Reaction $2$:-

$C_6{H}_5-CH=CH-\stackrel{\underset{||}{O}}{C}-C{H}_3\underset{{\left(C{H}_3\right)}_{2}CH-OH}{\overset{Al{\left(OCH{Me}_2\right)}_3}{\to }}{C}_6{H}_5-CH=CH-\stackrel{\underset{|}{OH}}{CH}-C{H}_3\Rightarrow$ Degree of unsaturation $=5$

Reaction $3$:-

$C_6{H}_5-CH=CH-\stackrel{\underset{|}{OH}}{CH}-C{H}_3\underset{\left(2\right)H^{+}}{\overset{\left(1\right)NaOI}{\to }}{C}_6{H}_5-CH=CH-\stackrel{\underset{||}{O}}{C}-OH\Rightarrow$ Degree of unsaturation $=6$

Therefore,

Degree of unsaturation present in compound $(A+B+C)$ is $6+5+6=17$.