31 Year NEET Previous Year Questions: Aldehydes, Ketones & Carboxylic Acids - 2 - NEET MCQ

Aldol condensation is given by the
compounds which contain α hydrogen
atom. As the given compound does not
contain α hydrogen atom. Hence it does not undergo aldol condensation.

The ester having α hydrogen atom show
Claisen condensation reaction. We know that ethyl benzoate (C₆H₅COOC₂H₅) does not contain α-hydrogen. Therefore
C₆H₅COOC₂H₅ does not undergo Claisen self condensation.

By oxidation of tertiary alcohol with stronger oxidising agents ketones may be formed along with carboxylic acid.

Iodoform test is exhibited by ethyl alcohol acetaldehyde, acetone methyl ketones and those alcohols which possess CH₃CH(OH)- group. As 3-pentanone does not contain
CH₃CO-group as therefore it does not give iodoform test.

(As it has a chiral C-atom thus it is optically active)

This reaction is known as clemmensen's
reduction.

In CH₂ = CH—CHO due to — M effect
of — CHO group polarization of electron
takes place as follows

Hence partial polarization is represented as

Catalyst used in Rosenmund reduction is Pd/
BaSO₄. Rosenmund Reduction is used for
reduction of acid chloride.

Acetophenone is a ketone, cyclopentane
doesn’t contain (4n + 2)π electron hence is
not aromatic. Diastase is an enzyme used in
the preparation of Maltose (Malt sugar, C₁₂
H₂₂ O₁₁) through hydrolysis of starch.

Tollen's reagent is used to detect of
aldehydes. Tollen's reagent is an ammonical
solution of silver nitrate. When aldehyde is
added to Tollen's reagent, silver oxide is
reduced to metallic silver which deposits as
mirror.

Grignard reagent forms addition product with
bubbled carbondioxide which on hydrolysis
with HCl yields benzoic acid.

It is a simple Cannizzro reaction.

Carbonyl compounds (aldehydes and
ketones) are obtained by the oxidation of 1°
and 2° alcohols respectively. Among the
given options, only (a) is 2° alcohol hence it
can be oxidized to ketone.

Among the given options, only PCl₅ can
convert an alcoholic group as well as a
carboxyl group to chloride.

Formalin is an aqueous solution (40%) of formaldehyde.

 I₂ and NaOH react with acetophenone
(C₆H₅COCH₃) to give yellow ppt. of CHI₃ but benzophenone (C₆H₅COC₆H₅) does not and hence can be used to distinguish between them. Oxidation of methyl ketones with sodium Hypoiodite (NaOI) or (I₂ +NaOH) gives iodoform (CHI₃) but not in case of benzophenone.

Acetaldehyde reacts only with nucleophiles. Since the mobile p electrons of carbon– oxygen double bond are strongly pulled towards oxygen, carbonyl carbon is electrondeficient and carbonyl oxygen is electronrich.
The electron deficient (acidic) carbonyl
carbon is most susceptible to attack by
electron rich nucleophilic reagents, that is, by base. Hence the typical reaction of aldehydes and ketones is nucleophilic
addition.

Ketones on oxidation give carboxylic acids with lesser number of carbon atoms, i.e.,

Pinacolone is 3,3-dimethyl-2 butanone.