Aldehydes, Ketones & Acids · JEE Advanced previous year questions

2024 1 question

1. Q442024 · 26 May 2024 · Paper 1· Numerical answer

   Complete reaction of acetaldehyde with excess formaldehyde, upon heating with conc. NaOH solution, gives $\mathbf{P}$ and $\mathbf{Q}$. Compound $\mathbf{P}$ does not give Tollens’ test, whereas $\mathbf{Q}$ on acidification gives positive Tollens’ test. Treatment of $\mathbf{P}$ with excess cyclohexanone in the presence of catalytic amount of $p$-toluenesulfonic acid (PTSA) gives product $\mathbf{R}$. Sum of the number of methylene groups ($-\mathrm{C}{\mathrm{H}}_2-$) and oxygen atoms in $\mathbf{R}$ is ____.

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   Answer: 18