Question

In the Victor-Meyer's test, the colour given by $1^{\circ}$, $2^{\circ}$and $3^{\circ}$ alcohols are respectively :

• A. Red, colourless, blue
• B. Red, blue, colourless
• C. Colourless, red, blue
• D. Red, blue, violet

Answer 1

The Correct Option is B

The Victor-Meyer test is a qualitative test used to distinguish between primary (1^{\circ}), secondary (2^{\circ}), and tertiary (3^{\circ}) alcohols based on the color change of the indicator used. The mechanism involves the conversion of alcohols to different types of nitrites, which react differently to produce distinct colors.

1. In the case of 1^{\circ} alcohols, the test gives a red color. This is because they transform into the corresponding aldehydes upon oxidation, which further react to give a red dye.
2. For 2^{\circ} alcohols, they are oxidized to ketones, which result in a blue color in the test.
3. Tertiary alcohols (3^{\circ}) do not undergo oxidation under similar conditions and remain unchanged, giving a colorless result.

Based on these explanations, let's examine the given options:

• Red, colourless, blue: Inconsistent with the above explanation.
• Red, blue, colourless: Correct sequence as per the Victor-Meyer test results for 1^{\circ}, 2^{\circ}, and 3^{\circ} alcohols, respectively.
• Colourless, red, blue: Incorrect, does not match the expected results based on alcohol reactivity.
• Red, blue, violet: Incorrect as tertiary alcohols should be colorless, not violet.

Thus, the correct answer is: Red, blue, colourless.