CBSE 2025 · Region 4 · Set 1 · Q31 · 5 marks
(i)Complete the following reactions by writing the structure of the main products :(I)
(II)\[\left(\mathrm{CH}_{3}\right) \] \[{ }_{2} \mathrm{Cd}+2 \mathrm{CH}_{3} \mathrm{COCl} \longrightarrow \](III)(ii)Give simple chemical test to distinguish between the following pairs of compounds :(I)Ethyl benzoate and benzoic acid $\displaystyle 1$(II)Propanal and propanone(i)Complete each synthesis by giving missing starting material, reagent or products :(I)(II)(III)(ii)Carry out the following conversions :(I)Benzaldehyde to Benzophenone(II)Benzaldehyde to $\displaystyle 3$-phenyl propanol
(i)
Complete the following reactions by writing the structure of the main products :
(I)
(II)
\[\left(\mathrm{CH}_{3}\right) \] \[{ }_{2} \mathrm{Cd}+2 \mathrm{CH}_{3} \mathrm{COCl} \longrightarrow \]
(III)
(ii)
Give simple chemical test to distinguish between the following pairs of compounds :
(I)
Ethyl benzoate and benzoic acid $\displaystyle 1$
(II)
Propanal and propanone
(i)
Complete each synthesis by giving missing starting material, reagent or products :
(I)
(II)
(III)
(ii)
Carry out the following conversions :
(I)
Benzaldehyde to Benzophenone
(II)
Benzaldehyde to $\displaystyle 3$-phenyl propanol
Marking-scheme solution
(i)
(I)
(II)
CH3COCH3
(III)
(ii)
(I)
Benzoic acid with Sodium bicarbonate gives brisk effervescence. No reaction with
Ethyl benzoate
(ii)
Propanal, when heated with ammoniacal solution of silver nitrate (Tollens’ reagent)
gives silver mirror. No reaction with propanone
(i)
(I)
(II)
1.(BH3)$\displaystyle 2$, 2.H2O2/OH- , 3.PCC
(b)
(ii)
(I)
(II)
C6H5CHO CH3CHO, dil NaOH ,∆ C6H5CH=CHCHO H2/Ni C6H5CH2CH2CH2OH
Aldehydes, Ketones and Carboxylic AcidsChemical Reactions of Aldehydes, Ketones and Carboxylic AcidsApplylong_answerhard
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CBSE Class 12 Chemistry past-paper question from the 2025board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.