Aldehydes, Ketones & Acids · JEE Main previous year questions

2024 5 questions

1. Q672024 · 9 Apr 2024 · Shift 2

   Which of the following compounds will give silver mirror with ammoniacal silver nitrate? A. Formic acid B. Formaldehyde C. Benzaldehyde D. Acetone Choose the correct answer from the options given below :

   1. A.B and C only
   2. B.C and D only
   3. C.A, B and C only
   4. D.A only
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   Answer: C

2. Q842024 · 5 Apr 2024 · Shift 2· Numerical answer

   Considering acetic acid dissociates in water, its dissociation constant is $6.25\times 10^{-5}$. If $5\mathrm{mL}$ of acetic acid is dissolved in 1 litre water, the solution will freeze at $-x\times 10^{-2\circ }\mathrm{C}$, provided pure water freezes at $0^{\circ }\mathrm{C}$. $x=$ ____. (Nearest integer) Given : $({\mathrm{K}}_{\mathrm{f}}{)}_{\text{water}}=1.86\mathrm{K}\mathrm{kg}\mathrm{mo}{\mathrm{l}}^{-1}$ density of acetic acid is $1.2\mathrm{g}\mathrm{m}{\mathrm{L}}^{-1}$. molar mass of water $=18\mathrm{g}\mathrm{mo}{\mathrm{l}}^{-1}$. molar mass of acetic acid$=60\mathrm{g}\mathrm{mo}{\mathrm{l}}^{-1}$. density of water $=1\mathrm{g}\mathrm{c}{\mathrm{m}}^{-3}$ Acetic acid dissociates as $\mathrm{C}{\mathrm{H}}_3\mathrm{COOH}\rightleftharpoons \mathrm{C}{\mathrm{H}}_3\mathrm{CO}{\mathrm{O}}^{\ominus }+{\mathrm{H}}^{\oplus }$

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   Answer: 19

3. Q872024 · 5 Apr 2024 · Shift 2· Numerical answer

   In the Claisen-Schmidt reaction to prepare $351\mathrm{g}$ of dibenzalacetone using $87\mathrm{g}$ of acetone, the amount of benzaldehyde required is ____ $\mathrm{g}$. (Nearest integer)

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   Answer: 318

4. Q632024 · 4 Apr 2024 · Shift 1

   Given below are two statements : Statements I : Acidity of $\alpha$-hydrogens of aldehydes and ketones is responsible for Aldol reaction. Statement II : Reaction between benzaldehyde and ethanal will NOT give Cross - Aldol product. In the light of the above statements, choose the most appropriate answer from the options given below :

   1. A.Both Statement I and Statement II are incorrect
   2. B.Statement I is correct but Statement II is incorrect
   3. C.Both Statement I and Statement II are correct
   4. D.Statement I is incorrect but Statement II is correct
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   Answer: B

5. Q872024 · 29 Jan 2024 · Shift 1· Numerical answer

   From the compounds given below, number of compounds which give positive Fehling's test is _________. Benzaldehyde, Acetaldehyde, Acetone, Acetophenone, Methanal, 4-nitrobenzaldehyde, cyclohexane carbaldehyde.

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   Answer: 3