Q143 / 200 · MHT CET - Medical 2026 (21 April Shift 1) · Chemistry
Identify a catalyst used in Stephen reaction from the following.
- A$\text{ZnCl}_2$ and HCl
- B$\text{HgCl}_2$ and HCl
- Correct answerC$\text{SnCl}_2$ and HCl
- DAgCl and HCl
Solution
The Stephen reaction involves the reduction of an alkyl cyanide (nitrile) to the corresponding aldehyde.
The reagents used in this reaction are stannous chloride ($\text{SnCl}_2$) and hydrochloric acid ($\text{HCl}$).
The reaction proceeds via the formation of an imine hydrochloride intermediate, which upon hydrolysis yields the aldehyde.
$R-C \equiv N + \text{SnCl}_2 + \text{HCl} \rightarrow R-CH=NH \cdot \text{HCl} \xrightarrow{H_3O^+} R-CHO + \text{NH}_4^+$
Therefore, the correct catalyst/reagent is $\text{SnCl}_2$ and $\text{HCl}$.
Answer: $\text{SnCl}_2$ and HCl
The reagents used in this reaction are stannous chloride ($\text{SnCl}_2$) and hydrochloric acid ($\text{HCl}$).
The reaction proceeds via the formation of an imine hydrochloride intermediate, which upon hydrolysis yields the aldehyde.
$R-C \equiv N + \text{SnCl}_2 + \text{HCl} \rightarrow R-CH=NH \cdot \text{HCl} \xrightarrow{H_3O^+} R-CHO + \text{NH}_4^+$
Therefore, the correct catalyst/reagent is $\text{SnCl}_2$ and $\text{HCl}$.
Answer: $\text{SnCl}_2$ and HCl
Hence, the correct answer is option: 'C'.