JEE Main 2022 · 29 July · evening · Single correct · +4 / −1
In liquation process used for tin (Sn), the metal :
- (a) is reacted with acid.
- (b) is dissolved in water.
- (c) is brought to molten form which is made to flow on a slope.
- (d) is fused with NaOH
Answer and solution
Answer (c) is brought to molten form which is made to flow on a slope.
Solution
Chemistry ma’am · 4 steps
Liquation works on melting points: tin melts early and runs down the slope, leaving the impurities behind.
- What liquation uses. Liquation refines a metal that melts at a much lower temperature than its impurities. Tin melts at about 232 °C, far below the melting points of impurities such as iron, copper and their oxides.
- How it is done. Impure tin is placed on the sloping hearth of a furnace and heated just above the melting point of tin. Tin melts and flows down the slope into a collecting vessel. The high-melting impurities stay behind on the hearth as solid dross.
- Why not the others. Liquation is a purely physical separation. No acid, water or NaOH is involved, so no chemical reaction or dissolving happens.
- So. In liquation the tin is brought to the molten state and made to flow on a slope, which is option (c).
The idea to keep. Pick the refining method from the physical property it uses: liquation needs a low melting point, distillation a low boiling point, electrolytic refining a metal that can be deposited at the cathode.
Answer from the NTA final answer key. Solution by PrepWiser.