Refining using liquation method is the most suitable for metals with

We need to identify which property makes a metal most suitable for refining by the liquation method.

Liquation is a metallurgical method used to refine metals. In this method, the impure metal is placed on the sloping hearth of a reverberatory furnace and heated gently. The metal with a low melting point melts and flows down the slope, leaving behind the higher-melting impurities on the hearth.

The essential condition for liquation to work is that the metal must have a low melting point compared to its impurities. This way, the metal melts at a relatively low temperature while the impurities remain solid.

Liquation is commonly used for refining metals like Tin (Sn) with melting point $$232°C$$, Bismuth (Bi) with melting point $$271°C$$, and Lead (Pb) with melting point $$327°C$$. All these metals have relatively low melting points.

Option A: Low melting point — Correct. This is the key requirement for liquation.

Option B: High boiling point — Not specifically relevant to liquation.

Option C: High electrical conductivity — This is relevant to electrolytic refining, not liquation.

Option D: Less tendency to be soluble in melts than impurities — This is not the correct description of liquation.

Hence, the correct answer is Option A: Low melting point.