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Question: The product of ozonolysis of an alkene is ethanal and methanal, then that alkene is A.\[{\text{C}}...

The product of ozonolysis of an alkene is ethanal and methanal, then that alkene is
A.CH3CCCH3{\text{C}}{{\text{H}}_3} - {\text{C}} \equiv {\text{C}} - {\text{C}}{{\text{H}}_3}
B.CH3CH=CHCH3{\text{C}}{{\text{H}}_3} - {\text{CH}} = {\text{CH}} - {\text{C}}{{\text{H}}_3}
C.CH3CH=CH2{\text{C}}{{\text{H}}_3} - {\text{CH}} = {\text{C}}{{\text{H}}_2}
D.CH3CCH{\text{C}}{{\text{H}}_3} - {\text{C}} \equiv {\text{CH}}

Explanation

Solution

In the above question we have been given the product of ozonolysis and we have to search for a reactant. Oxygen adds up in the unsaturation of alkenes and the total number of carbon remains same in reactant and product.

Complete step by step answer:
Ozonolysis is an organic reaction in which the ozone molecule is used for breaking the unsaturated bond and converting it into a carbonyl group.
We have been given two products that are formed by ozonolysis of an alkene. So the reactant species is an alkene that means it has a double bond in it. If we look at the above options, option A and D has triple bonds or are alkynes. Hence we can eliminate option A and D from here.
The ‘al’ function group refers to the aldehyde functional group.
The chemical formula for methanal is HCHO{\text{HCHO}}. The formula for ethanal is CH3CHO{\text{C}}{{\text{H}}_3}{\text{CHO}}. In ozonolysis oxygen gets added up in a double bond. Hence the number of carbon should remain constant in the product and reactant. In the two products forms have total 3 carbons, one carbon in HCHO{\text{HCHO}} and two carbon in CH3CHO{\text{C}}{{\text{H}}_3}{\text{CHO}}. According to this the reactant should have total tree carbon which is in option CH3CH=CH2{\text{C}}{{\text{H}}_3} - {\text{CH}} = {\text{C}}{{\text{H}}_2}. The reaction occurs as follow:
CH3CH=CH2ozonolysisHCHO+CH3CHO{\text{C}}{{\text{H}}_3} - {\text{CH}} = {\text{C}}{{\text{H}}_2}\xrightarrow{{{\text{ozonolysis}}}}{\text{HCHO}} + {\text{C}}{{\text{H}}_3}{\text{CHO}}

Hence the correct option is C.

Note:
Ozone has a molecular formula as O3{{\text{O}}_3}. It is an allotrope of oxygen and is less stable than oxygen. It has formed a very thin layer on the earth’s atmosphere and most of its concentration lies in the stratosphere. It is colourless to pale blue in colour and is soluble in carbon tetrachloride.