JEE Main 2023 · 31 January · morning · Single correct · +4 / −1

Match items of column I and II
Correct match is

Column I (Mixture of compounds)Column II (Separation Technique)
A.H₂O/CH₂Cl₂i.Crystalization
B.ii.Differential solvent extraction
C.Kerosene / Naphthaleneiii.Column chromatography
D.C₆H₁₂O₆/NaCliv.Fractional Distillation
  1. (a) A-(ii), B-(iv), C-(i), D-(iii)
  2. (b) A-(iii), B-(iv), C-(ii), D-(i)
  3. (c) A-(i), B-(iii), C-(ii), D-(iv)
  4. (d) A-(ii), B-(iii), C-(iv), D-(i)
Answer and solution

Answer (d) A-(ii), B-(iii), C-(iv), D-(i)

Solution

Chemistry ma’am · 3 steps

Ask what each pair is physically: two liquids, two solids, or two compounds of different polarity.

  1. Match by property. Every separation technique uses one difference between the two components. Find that difference for each mixture, and the technique follows.
    MixtureWhat differsTechnique
    A. H₂O/CH₂Cl₂Two immiscible liquids that form separate layers(ii) differential solvent extraction
    B. α-tetralone / p-nitrophenolDifferent polarity (ketone versus phenol with -NO₂), so they adsorb differently on silica(iii) column chromatography
    C. Kerosene / naphthaleneNaphthalene dissolves in kerosene. Both are volatile, with boiling points that are not far apart(iv) fractional distillation
    D. C₆H₁₂O₆/NaClTwo non-volatile solids with different solubility in a chosen solvent(i) crystallisation
  2. Rule out quickly. A must be (ii), which leaves only (a) and (d). C must be (iv), since kerosene is a liquid and cannot be crystallised. That removes (a).
  3. So. The correct match is A-(ii), B-(iii), C-(iv), D-(i), which is option (d).

The idea to keep. Immiscible liquids: solvent extraction. Miscible liquids with close boiling points: fractional distillation. Solids differing in solubility: crystallisation. Different polarity: chromatography.

Answer from the NTA final answer key. Solution by PrepWiser.

Study Purification & Characterisation of Organic Compounds

Asked about 130 times in JEE Main since 2020. This question is from 2023.