Question

$\begin{array}{cc}\text{Column I (Process)}& \text{Column II (Electrolyte)}\\ \text{(A) Downs cell process}& \text{(P) Fused}MgC{l}_2\\ \text{(B) Dow seawater process}& \text{(Q) Fused}(A{l}_2{O}_3+N{a}_{3}Al{F}_6)\\ \text{(C) Hall-Heroult process}& \text{(R) Fused}KH{F}_2\\ \text{(D) Moissan process}& \text{(S) Fused}(40\%NaCl+60\%CaC{l}_2)\end{array}$

• A. A - Q; B - P; C - S; D - R
• B. A - R; B - S; C - Q; D - P
• C. A - S; B - P; C - Q; D - R
• D. A - S; B - R; C - Q; D - P

Answer 1

The correct option is C A - S; B - P; C - Q; D - R

(a) In Downs cell, molten $MgC{l}_2$​ is electrolyzed, the electrolyte used in the cell is a fused mixture of $40\%NaCl$ and $60\%CaC{l}_2$.

(b) In Dow process, $Mg(OH{)}_2$​ is precipitated from seawater by slurrying with calcined dolomite and then converting it to $MgC{l}_2$​ by reacting with $HCl$. In Dow seawater process, the electrolyte used is fused $MgC{l}_2$​.

(c) In the Hall-Heroult process, the electrolyte used is a fused mixture of $A{l}_2{O}_3$ and $N{a}_{3}Al{F}_6$.

(d) In Moissan process, the electrolyte used is fused $KH{F}_2$​.