Question

In this reaction,
$$C{H_3}CHO + HCN \to $$     \[C{{H}_{3}}CH\left( OH \right)CN\xrightarrow{H.OH}\]      $$C{H_3}CH\left( {OH} \right)COOH$$
an asymmetric centre is generated. The acid obtained would be

A. $$50\% \,D + 50\% \,L{\text{ - isomer}}$$  
B. $$20\% \,D + 80\% \,L{\text{ - isomer}}$$
C. $$D{\text{ - isomer}}$$
D. $$L{\text{ - isomer}}$$
Answer :   $$50\% \,D + 50\% \,L{\text{ - isomer}}$$
Solution :
Lactic acid obtained in the given reaction is an optically active compound due to the presence of chiral $$C$$ - atom. It exits as $$d$$  and $$l$$ - forms whose ratio is 1 : 1.
Aldehyde and Ketone mcq solution image

Releted MCQ Question on
Organic Chemistry >> Aldehyde and Ketone

Releted Question 1

The reagent with which both acetaldehyde and acetone react easily is

A. Fehling’s reagent
B. Grignard reagent
C. Schiff’s reagent
D. Tollen’s reagent
Releted Question 2

The Cannizzaro reaction is not given by

A. trimethylacetaldehye
B. acetaldehyde
C. benzaldehyde
D. formaldehyde
Releted Question 3

The compound that will not give iodoform on treatment with alkali and iodine is :

A. acetone
B. ethanol
C. diethyl ketone
D. isopropyl alcohol
Releted Question 4

Polarisation of electrons in acrolein may be written as

A. $$\mathop {C{H_2}}\limits^{{\delta ^ - }} = CH - \mathop {CH}\limits^{{\delta ^ + }} = O$$
B. $$\mathop {C{H_2}}\limits^{{\delta ^ - }} = CH - CH = \mathop O\limits^{{\delta ^ + }} $$
C. $$\mathop {C{H_2}}\limits^{{\delta ^ - }} = \mathop {CH}\limits^{{\delta ^ + }} - CH = O$$
D. $$\mathop {C{H_2}}\limits^{{\delta ^ + }} = CH - CH = \mathop O\limits^{{\delta ^ - }} $$

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Aldehyde and Ketone


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