Question:
Write chemical equation for identifying primary and secondary alcohol.
Write chemical equation for identifying primary and secondary alcohol.
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Remember: Primary alcohol → oxidises to acid; Secondary alcohol → oxidises to ketone; Tertiary alcohol → generally resistant to oxidation.
Updated On: Oct 7, 2025
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Solution and Explanation
Step 1: Oxidation test (using acidified \(K_2Cr_2O_7\)).
\begin{itemize} \item
Primary alcohols: Oxidised to aldehydes, which further oxidise to carboxylic acids. \[ R-CH_2OH \;\xrightarrow{[O]}\; R-CHO \;\xrightarrow{[O]}\; R-COOH \] \item
Secondary alcohols: Oxidised to ketones only. \[ R-CHOH-R' \;\xrightarrow{[O]}\; R-CO-R' \] \end{itemize} Step 2: Lucas Test (ZnCl\(_2\)/HCl).
\begin{itemize} \item Primary alcohols react very slowly (no turbidity at room temp). \item Secondary alcohols give turbidity within 5–10 minutes. \end{itemize} Conclusion:
Primary and secondary alcohols can be distinguished by their oxidation behaviour and Lucas test.
\begin{itemize} \item
Primary alcohols: Oxidised to aldehydes, which further oxidise to carboxylic acids. \[ R-CH_2OH \;\xrightarrow{[O]}\; R-CHO \;\xrightarrow{[O]}\; R-COOH \] \item
Secondary alcohols: Oxidised to ketones only. \[ R-CHOH-R' \;\xrightarrow{[O]}\; R-CO-R' \] \end{itemize} Step 2: Lucas Test (ZnCl\(_2\)/HCl).
\begin{itemize} \item Primary alcohols react very slowly (no turbidity at room temp). \item Secondary alcohols give turbidity within 5–10 minutes. \end{itemize} Conclusion:
Primary and secondary alcohols can be distinguished by their oxidation behaviour and Lucas test.
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