Q.Which method of refining will you suggest for an element in which impurities present have chemical properties close to the properties of that elements?

Where impurities closely resemble the element chemically, methods relying on chemical reactivity differences (e.g. selective displacement) would fail to distinguish them. Chromatography instead exploits subtle differences in how strongly each species adsorbs onto a stationary phase, allowing separation even when the species are chemically very similar. …

Step 1 – Why chemically-similar impurities are hard to separate

Many refining/purification approaches (e.g. selective chemical displacement, or exploiting a big difference in reactivity/oxidation state) fail when the impurity present behaves almost identically, chemically, to the element being purified — there's no strong chemical "handle" to distinguish and remove it.

Step 2 – How chromatography gets around this

Chromatographic separation does not rely on a gross chemical difference; it relies on subtle differences in the strength of physical adsorption of each species onto a common stationary adsorbent (such as alumina). Even substances that are chemically very similar typically still differ slightly in their adsorption affinity, and this small difference is enough for the mobile phase (eluant) to carry them down the column at different rates, separating them into distinct bands/fractions.

Step 3 – Conclusion …

Recognise that chemically-similar impurities defeat reactivity-based separation methods, whereas chromatography works on adsorption-affinity differences — a …

• Suggesting electrolytic refining, which distinguishes species mainly by their differing reduction/oxidation behaviour — exactly what fails when impurities are chemically similar to the element. …