Preparations and Uses of Sodium Carbonate

Q.

A colourless aqueous solution contains nitrates of two metals, $\mathrm{X}$ and $\mathrm{Y}$. When it was added to an aqueous solution of $\mathrm{NaCl},$ a white precipitate was formed. This precipitate was found to be partially soluble in hot water to give a residue $\mathrm{P}$ and a solution $\mathrm{Q}$. The residue $\mathrm{P}$was soluble in aqueous ${\mathrm{NH}}_3$and also in excess sodium thiosulfate. The hot solution $\mathrm{Q}$ gave a yellow precipitate with $\mathrm{KI}$. The metals $\mathrm{X}$and $\mathrm{Y}$, respectively, are:

1. $\mathrm{Ag}\mathrm{and}\mathrm{Pb}$

2. $\mathrm{Ag}\mathrm{and}\mathrm{Cd}$

3. $\mathrm{Cd}\mathrm{and}\mathrm{Pb}$

4. $\mathrm{Cd}\mathrm{and}\mathrm{Zn}$

Q. 48. Sodium salt of an acid gives propane when distilled with sodalime. On kolbe electrolysis it will give

Q. Which of the following compounds is consumed during the preparation of $N{a}_{2}C{O}_3$ by Solvay's process?

1. $N{H}_3+CaC{O}_3+NaCl$
2. $N{H}_{4}Cl+CaO+NaCl$
3. $CaC{O}_3+NaCl$
4. $NaCl+N{H}_{4}HC{O}_3$

Q. $N{a}_{2}C{O}_3.10H_{2}O$, when exposed to air, looses water of crystallization and finally gives:

1. $N{a}_{2}C{O}_3.4H_{2}O$
2. $N{a}_{2}C{O}_3.H_{2}O$
3. $N{a}_{2}C{O}_3.7H_{2}O$
4. $N{a}_{2}C{O}_3.9H_{2}O$

Q. Which of the following compounds is consumed during the preparation of $N{a}_{2}C{O}_3$ by Solvay's process?

1. $N{H}_3+CaC{O}_3+NaCl$
2. $N{H}_{4}Cl+CaO+NaCl$
3. $CaC{O}_3+NaCl$
4. $NaCl+N{H}_{4}HC{O}_3$