Answer
a) 2-methyl-1-butene
b) 2,4-dimethyl-1,4-pentadiene
c) 3-ethyl-7-methyl-4-octene
d) 3-bromoheptyne
e) 7-chloro-2,5,5-trimethyl-3-heptyne
f) 4-ethyl-3-methyloctyne
Work Step by Step
a) No. of C in straight chain = 4. hence, root name is 'but' and ending name is 'ene' as there is one double bond present in the compound. Now, numbering the C atom in straight chain so that double bonded C gets the minimum number. So, numbering is done from right to left. Now, we see that one methyl group is present as a substitute at C2 position. So, '2-methyl' is added before root name and we get the complete name.
b) No. of C in straight chain = 5. hence, root name is 'pent' and we see that two double bond are present in the compound. so, ending name is 'diene'. Numbering the C atom in straight chain so that the double bonded C get the minimum number. So, numbering is done from left to right and double bonded C get the position C1 and C4. So, 1,4-pentadiene.
Now, two methyl groups are present at C2 and C4 position. So, 2,4-dimethyl is added before root name and we get the complete name.
c) No. of C in straight chain = 8. hence, root name is 'oct' and ending name is 'ene' for one double bond present. Now, numbering the C atom in straight chain so that the double bonded C gets the minimum number and also look for substitute to get the minimum position. So, numbering is done from left to right and double bonded C gets C4 position. So, '4-octene'. Now, one ethyl is present at C3 position and one methyl is present at C7 position. So, 3-ethyl-7-methyl' is added before root name and we get the complete name.
d) No. of C in straight chain = 7. hence, root name is 'hept' and ending name is 'yne' for one triple bond present in the compound. Now, numbering the C in straight chain so that the triple bonded C gets the minimum number. so, the numbering is done from right to left so that triple bonded C gets C1 position. Now, we see that one Br group is present at C3 position. so,3-bromo is added before root name and we get the complete name.
e) No. of C in longest straight chain = 7. hence, root name is 'hept' and ending name is 'yne' for triple bond present in the compound. Numbering of C atom in straight chain is done so that the triple bonded C gets the minimum number. So, numbering is done from right to left. Triple bonded C is at C3 position : So, 3-heptyne. Now, we see that one Cl is present at C7 position , three methyl groups are present at C2, C5 and C5 position respectively. So, '7-chloro-2,5,5-trimethyl' is added before root name and we get the complete name.
f) No. of C in longest straight chain = 8. hence, root name is 'oct' and ending name is 'yne' for triple bond present in that compound. Numbering the C atom in straight chain is done so that the triple bonded C gets the minimum number. So, numbering is done from left to right so that the triple bonded C gets C1 position. Now, we see that one ethyl group is present at C4 position and one methyl group is present at C3 position. So, '4-ethyl-3-methyl' is added before root name and we get the complete name.
