COMEDK 2025 Afternoon Shift | Aldehyde and Ketone Question 3 | Chemistry

The increasing order of boiling points of 5 compounds having comparable molar masses is as follows: Methoxyethane $<$ Propanone $<$ Propanal $<$ Propan-1-ol

During nucleophilic addition of HCN to RCHO , the hybridisation changes from $\mathrm{sp}^2$ to $\mathrm{sp}^3$ and a tetrahedral intermediate is formed.

Acetone undergoes Wolff Kishner reaction to yield Propane.

The order of reactivity towards Nucleophilic attack is Methanal $>$ Di-tert.butyl ketone $>$ Benzaldehyde $>$ Acetophenone

COMEDK 2025 Afternoon Shift

MCQ (Single Correct Answer)

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An organic compound " A " reacts with $\mathrm{Zn} / \mathrm{Hg}$ / Conc. HCl to form p-Xylene. It reduces Tollen's reagent and on oxidation with $\mathrm{KMnO}_4 / \mathrm{H}^{+}$it yields 1, 4-benzenedicarboxylic acid. Identify compound A.

p-methylbenzaldehyde.

p- Cresol.

m-Cresol.

4-Methylacetophenone.

COMEDK 2025 Morning Shift

MCQ (Single Correct Answer)

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Two statements, one Assertion (A) and the other Reason (R) are given. Choose the correct option.

Assertion: Compound $[\mathrm{X}]$ reacts with Hydrazine in presence of $\mathrm{KOH} /$ Glycol to form the product $[\mathrm{Y}]$.

COMEDK 2025 Morning Shift Chemistry - Aldehyde and Ketone Question 6 English

Reason: Reduction reaction occurs and Carbonyl group is reduced to Methylene group.

Both A and R are correct but R is not the correct explanation of A .

Both A and R are correct and R is the correct explanation of A .

A is wrong but R is correct.

A is correct but R is wrong.

COMEDK 2025 Morning Shift

MCQ (Single Correct Answer)

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Which one of the following reactions does not give the correct combination of reactants and the major products formed in the reaction?

$\mathrm{CH}_3-\mathrm{CO}-\mathrm{CH}_3+\mathrm{NH}_2-\mathrm{NH}-\mathrm{CO}-\mathrm{NH}_2($ weakly basic $) \rightarrow\left(\mathrm{CH}_3\right)_2 \mathrm{C}=\mathrm{N}-\mathrm{NH}-\mathrm{CO}-\mathrm{NH}_2$

$\mathrm{CH}_3 \mathrm{CHO}+2 \mathrm{C}_2 \mathrm{H}_5 \mathrm{OH}($ dry HCl gas $) \leftrightharpoons \mathrm{CH}_3-\mathrm{CH}-\left(\mathrm{OC}_2 \mathrm{H}_5\right)_2$

$\mathrm{CH}_3-\mathrm{CH}=\mathrm{CH}-\mathrm{CH}_2-\mathrm{CH}_2-\mathrm{CN}$ $\xrightarrow[\text { (ii). } \mathrm{H}_2 \mathrm{O}]{\text { (i). DIBAL-H }} \mathrm{CH}_3-\left(\mathrm{CH}_2\right)_4-\mathrm{CHO}$

$\mathrm{C}_6 \mathrm{H}_5-\mathrm{CO}-\mathrm{CH}_3+\mathrm{I}_2+\mathrm{Na}_2 \mathrm{CO}_3($ Heat $) \rightarrow \mathrm{CHI}_3+\mathrm{C}_6 \mathrm{H}_5 \mathrm{COO}^{--}$

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