Answer
a) heptanal
b) 3-ethyl-5-methyl-1-hexanal
c) 3-hexanone
d) 4,5-dimethyl-3-hexanone
e) 3,4-dimethylhexanoic acid
Work Step by Step
a) Total no. of C in straight chain = 7. hence, root name is 'hept' and ending name is 'anal' because the functional group present here is aldehyde (-CHO). So, the complete name is heptanal.
b) Total no. of C in straight chain = 6. hence, root name is 'hex' and ending name is 'anal' because the functional group present here is -CHO. Now, numbering the C atom in straight chain from 1 to 6 so that the C associated with CHO group gets C1 position. So, numbering will be done from right to left. Now, we see that one ethyl group is present as a substituent at C3 position and one methyl group is present as a substituent at C5 position. So, '3-ethyl-5-methyl' is added before root name and we get the complete name '3-ethyl-5-methyl-1-hexanal'.
c) Total no. of C in straight chain = 6. Hence, root name is 'hex' and ending name is 'anone' because the functional group present here is ketone (-CO-) . Now, numbering the C atom in straight chain so that the C associated with CO group gets the minimum number. So, the numbering is done from left to right and C associated with CO group gets C3 position. Hence, the complete name is 3-hexanone.
d) Total no. of C in straight chain = 6. hence, root name is 'hex' and ending name is 'anone' because the functional group present here is CO. Now, numbering the C atom in straight chain so that the C associated with CO group gets the minimum number. So, the numbering is done from left to right and C associated with CO group gets C3 position. Now, two methyl groups are present as a substituent at C4 and C5 position respectively. So, '4,5-dimethyl' is added before root name. The complete name is 4,5-dimethyl-3-hexanone.
e) Total no. of C in straight chain = 6. hence, root name is hex and ending name is 'anoic acid' because the functional group present here is carboxylic acid (-COOH). Now, numbering the C atom in straight chain so that the C associated with COOH gets C1 position. Hence, the numbering is done from right to left. Now, we see that two methyl groups are present at C3 and C4 position respectively. Hence, '3,4-dimethyl' is added before root name and we get the complete name i.e. 3,4-dimethylhexanoic acid.
