Question

Select the compound with incorrect principal group:-

• A. (a)
• B.
• C. (c)
• D. (d)

Answer 1

Answer: (A), (B)

The correct options are
A

(a)

B

when there are more than one functional groups,then the principal group is chosen in the following

decreasing order.

$-COOH$ > $-S{O}_{3}H$ > Esters > Acid halides > Amides > Imides >
aldehydes > Cyanides > isocyanides > Ketones > Alcohols and so on

(a) It has both a $-\stackrel{O}{\stackrel{||}{C}}-$ and $-\stackrel{O}{\stackrel{||}{C}}-OH$ in $C{H}_3-\stackrel{O}{\stackrel{||}{C}}-\stackrel{O}{\stackrel{||}{C}}-OH$ .Here $-\stackrel{O}{\stackrel{||}{C}}-OH$ has the

higher preference .Hence the given compound is a carboxylic acid and NOT a ketone.

(b) Has both $-\stackrel{O}{\stackrel{||}{C}}-$ and -OH groups.It is a ketone and not an alcohol.

(c) $C{H}_3-C{H}_2-\underset{CN}{\underset{|}{CH}}-CHO$ has both -CN as well as -CHO. -CN has higher preference than -CHO.

(d) It has both -CN and -COOH but has been rightly matched with "carboxylic acid".

Hence Ans:a,b