JEE Main · 2023 · Shift-ImediumPOC-023

Which of the following statement is correct for paper chromatography?

Practical Organic Chemistry · Class 11 · JEE Main Previous Year Question

Question

Which of the following statement is correct for paper chromatography?

Options
  1. a

    Water present in the mobile phase gets absorbed by the paper which then forms the stationary phase.

  2. b

    Water present in the pores of the paper forms the stationary phase.

  3. c

    Paper sheet forms the stationary phase.

  4. d

    Paper and water present in its pores together form the stationary phase.

Correct Answerb

Water present in the pores of the paper forms the stationary phase.

Detailed Solution

Step 1: Recall the Principle of Paper Chromatography

Paper chromatography is a type of partition chromatography. The separation occurs because compounds partition (distribute) between:

  • Stationary phase: the liquid held within the paper
  • Mobile phase: the organic solvent that moves up the paper by capillary action

Step 2: Identify What Acts as the Stationary Phase

The cellulose fibres of the paper are hydrophilic — they absorb water from the atmosphere and hold it in their pores. This water film within the pores of the paper is the actual stationary phase.

Step 3: Evaluate Each Option

(a) "Water in the mobile phase gets absorbed by paper → forms stationary phase" ❌ False. The stationary water is not from the mobile phase — it is the moisture already present in the paper (absorbed from atmosphere). The mobile phase moves through the paper and is NOT absorbed to become stationary.

(b) "Water present in the pores of the paper forms the stationary phase" ✅ True. Water molecules held in the pores of the cellulose fibres constitute the stationary phase.

(c) "Paper sheet forms the stationary phase" ❌ Incomplete/misleading. The paper itself (cellulose) is just the support — it holds the stationary water. Technically it is the water, not the cellulose, that acts as the stationary phase.

(d) "Paper and water together form the stationary phase" ❌ Not accurate — only the water held in the paper is the stationary phase. The cellulose is merely the support.

Step 4: Conclusion

Answer: (b) Water present in the pores of the paper forms the stationary phase

Key Points to Remember:

  • Paper chromatography = partition chromatography (NOT adsorption)
  • Stationary phase = water in pores of cellulose fibres
  • Mobile phase = organic solvent (moves by capillary action)
  • The paper supports the stationary water film but is not itself the stationary phase
  • Separation is based on differential partition coefficients of compounds between mobile and stationary phases

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Which of the following statement is correct for paper chromatography? (JEE Main 2023) | Canvas Classes