Name: Preparation of Alcohols
Uploaded: 2019-07-19
Duration: 4 min 43 s
Description: Alcohol is a psychosomatic drug and it is bad for health if consumed. However, it is a useful organic solvent in chemistry labs. Tune in to learn more about...

Question

Lithium reacts with alcohols in a similar way to sodium. A small piece of lithium metal is dropped onto a watch-glass containing propan-1-ol.

What difference would you expect to see if you used sodium instead of lithium in this reaction?

Accepted Answer

Lithium reacts with alcohols in a similar way to sodium. In the reaction with sodium, the O-H bond in the alcohol breaks. The reaction is similar to sodium’s reaction with water but less vigorous. In both cases, hydrogen gas is given off and a basic ionic compound is formed.

When a small piece of lithium metal is dropped onto a watch-glass containing propan-1-ol: propan-1-ol would produce lithium propoxide and hydrogen gas.

${CH}_{3} {CH}_{2} {CH}_{2} OH + Li \to {CH}_{3} {CH}_{2} {CH}_{2} O^{-} {Li}^{+} + H_{2}$

Hence, the observation when a small piece of lithium metal is dropped onto a watch-glass containing propan-1-ol would be the evolution of a colourless odourless gas(hydrogen)

In general:

alcohol + sodium $\to$ sodium alkoxide + hydrogen
alcohol + lithium $\to$ lithium alkoxide + hydrogen

Hence, if sodium is used instead of lithium in this reaction, then sodium alkoxide and hydrogen will be produced, instead of lithium alkoxide and hydrogen. Rest of the observation would remain same.

Lawrie Ryan and Roger Norris Solutions for Chapter: Alcohols, Esters and Carboxylic Acids, Exercise 5: Question

Lawrie Ryan Chemistry Solutions for Exercise - Lawrie Ryan and Roger Norris Solutions for Chapter: Alcohols, Esters and Carboxylic Acids, Exercise 5: Question

Questions from Lawrie Ryan and Roger Norris Solutions for Chapter: Alcohols, Esters and Carboxylic Acids, Exercise 5: Question with Hints & Solutions

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