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Which of the compounds with molecular formula $C_5H_{10}$ yields acetone on ozonolysis?
A
3-methyl-1-butene
B
cyclopentane
C
2-methyl-1-butene
D
2-methyl-2-butene
Detailed Solution
In ozonolysis, the $C=C$ bond is cleaved and each doubly bonded carbon is converted into a carbonyl group.
Acetone, $(CH_3)_2C=O$, is formed only if one of the doubly bonded carbons carries two methyl groups, i.e. the alkene contains the unit $(CH_3)_2C=$.
2-methyl-2-butene: $(CH_3)_2C=CH-CH_3 \xrightarrow{O_3}$ ozonide $\xrightarrow{H_2O,\ -H_2O_2} CH_3-CO-CH_3 + CH_3-CHO$
It gives acetone and acetaldehyde.
3-methyl-1-butene, $(CH_3)_2CH-CH=CH_2$, gives 2-methylpropanal and formaldehyde.
2-methyl-1-butene, $CH_2=C(CH_3)-CH_2CH_3$, gives butanone and formaldehyde.
Cyclopentane has no double bond and does not undergo ozonolysis.
So the compound is 2-methyl-2-butene.
Acetone, $(CH_3)_2C=O$, is formed only if one of the doubly bonded carbons carries two methyl groups, i.e. the alkene contains the unit $(CH_3)_2C=$.
2-methyl-2-butene: $(CH_3)_2C=CH-CH_3 \xrightarrow{O_3}$ ozonide $\xrightarrow{H_2O,\ -H_2O_2} CH_3-CO-CH_3 + CH_3-CHO$
It gives acetone and acetaldehyde.
3-methyl-1-butene, $(CH_3)_2CH-CH=CH_2$, gives 2-methylpropanal and formaldehyde.
2-methyl-1-butene, $CH_2=C(CH_3)-CH_2CH_3$, gives butanone and formaldehyde.
Cyclopentane has no double bond and does not undergo ozonolysis.
So the compound is 2-methyl-2-butene.