JEE Chemistry 2023 Question with Solution

Given: A column chromatography figure shows three bands with 'a' at the top, 'b' in the middle, and 'c' at the bottom.

Find: The incorrect statements among A, B, C, and D.

In column chromatography, the compound that is adsorbed more strongly stays higher in the column for a longer time. Hence, greater retention in the column indicates greater polarity.

From the figure and the extracted analysis:

$$a > b > c$$

for the order of polarity.

Therefore, the order of elution is:

$$c > b > a$$

So 'c' comes out first, then 'b', and 'a' comes out last.

Also, the time spent in the column is:

$$a > b > c$$

Now check each statement:

1. A. Compound 'c' is more polar than 'a' and 'b' — incorrect.
2. B. Compound 'a' is the least polar — incorrect.
3. C. Compound 'b' comes out of the column before 'c' and after 'a' — incorrect.
4. D. Compound 'a' spends more time in the column — correct.

Therefore, the incorrect statements are A, B, and C only. The correct option is B.

Given: Bands in the column are arranged as 'a' above 'b' above 'c'.

Find: Which statements are incorrect.

Key factors:

• Adsorption determines how long a compound remains in the column.
• The order of polarity determines the retention time.
• Time spent in the column is inversely proportional to the order in which the compounds come out of the column.

From the solution analysis:

• Order of polarity:

$$a > b > c$$

• Order of elution:

$$c > b > a$$

• Time spent in the column:

$$a > b > c$$

Thus, statement A is false, statement B is false, statement C is false, and statement D is true.

Therefore, the incorrect statements are A, B, and C only.