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Question: \( C{{H}_{3}}CHO+C{{H}_{2}}{{\left( COOH \right)}_{2}}\xrightarrow[\Delta ]{Pyridine}x \) ; x is: ...

CH3CHO+CH2(COOH)2→ΔPyridinexC{{H}_{3}}CHO+C{{H}_{2}}{{\left( COOH \right)}_{2}}\xrightarrow[\Delta ]{Pyridine}x ; x is:
A) CH3COOHC{{H}_{3}}COOH
B) C2H5COOH{{C}_{2}}{{H}_{5}}COOH
C) CH3CH=CHCOOHC{{H}_{3}}CH=CHCOOH
D) (COOH)CH=CH(COOH)(COOH)CH=CH(COOH)

Explanation

Solution

Hint : Two steps will occur in this reaction to give the final product. This happens due to the presence of pyridine and heat, in the first step water will be removed and in the second step, carbon dioxide will be removed. Thus, the final product will be formed accordingly.

Complete Step By Step Answer:
Let us first state the compounds given in the reaction, CH3CHOC{{H}_{3}}CHO is known as acetaldehyde, CH2(COOH)2C{{H}_{2}}{{(COOH)}_{2}} is known as malonic acid, it has a carboxyl functional group.
Now, due to the presence of pyridine and heat in this reaction, it will occur in two steps. The first step is reaction of Acetaldehyde ( CH3CHOC{{H}_{3}}CHO ) with Malonic acid ( CH2(COOH)2C{{H}_{2}}{{(COOH)}_{2}} ) and loses a water molecule. The water molecule comprises of 2 hydrogen and 1 oxygen, the oxygen atom is taken from Acetaldehyde ( CH3CHOC{{H}_{3}}CHO ) and 2 hydrogen atoms are taken from Malonic acid ( CH2(COOH)2C{{H}_{2}}{{(COOH)}_{2}} ), and thus water molecule is released.
CH3−CH=O+H2C(COOH)2C{{H}_{3}}-CH=O+{{H}_{2}}C{{(COOH)}_{2}}
From this, oxygen and hydrogen make water molecule and the remaining compound is given by,
CH3−CH=C(COOH)2C{{H}_{3}}-CH=C{{(COOH)}_{2}}
This product if obtained by heating the reactants the first time, further heating will give the more stable and final product. Through heating further, carbon dioxide is released from the first obtained product and we obtain the final product.
CH3−CH=CHCOOHC{{H}_{3}}-CH=CHCOOH
The above image shows the final product obtained.
Thus the correct option is C.

Note :
After obtaining the first product, carbon dioxide is released from the carboxyl group, and the hydrogen gets attached to the secondary carbon thus forming the final product. At the start of the reaction, two groups were there, hydroxyl and carboxyl, but at the end of the reaction only the carboxyl group remained. The obtained products are named according to IUPAC names and don’t have specific names.