Answer
a) 3-methylbutanal
b) cyclohexanone
c) 3,3-dibromopropanal
d) phenylpropanone
Work Step by Step
a) Count the number of C atoms in straight chain. It is 4. Hence, the word root is 'but'. Now, find the functional group present here. $-CHO$ group present here hence ending name will be 'anal'. One methyl ($-CH_{3}$) substituent is present at C3 position. Hence, '3-methyl' is added before word root while naming.
b) The given ring compound consists of 6 'carbons. Hence it is cyclohexane. One $-CO-$ group present in the ring. So, the ending name will be 'anone'. Hence, the name is cyclohexanone.
c) count the no. of C in straight chain. it is 3. hence the word root is 'prop'. Now, here main functional group is -CHO and it is present at one terminal position which is C1 carbon. Now numbering of C atoms is done from right side. We see that 2 bromine atom is at C3 position. So, we use '3,3-dibromo' before word root and the ending name is 'anal'.
d) Count the no. of C in straight chain. It is 3. hence the word root is 'prop'. Now, there is CO functional group present. so, the ending name is 'anone' and phenyl group is present as substituent. Hence, the name is phenylpropanone.
