Q.Which method of refining may be more suitable if element is obtained in minute quantity?

Step 1 – What limits bulk refining methods

Techniques like distillation, electrolytic refining, or zone refining generally work on a reasonably sized sample/charge of metal — they are geared towards processing appreciable quantities.

Step 2 – Why chromatography suits minute quantities

Chromatographic methods work on the principle of differential adsorption of different substances on a common adsorbent (stationary phase). Because separation here depends on a physicochemical affinity difference rather than on processing a large bulk of material, this technique can effectively separate and purify even very small (trace) amounts of an element from associated impurities, using a small column and a suitable eluant.

Step 3 – Practical note …

Match the refining method to the constraint given — 'minute quantity' immediately points to chromatography, since it is specifically noted (in the same NCERT passage …

• Suggesting distillation or electrolytic refining, which are geared toward processing a reasonable bulk quantity of metal, not trace amounts. …