Write the preparation of following compounds with balanced chemical equation: (i) Baking soda (ii) Bleaching powder (iii) Plaster of Paris

\(\displaystyle \mathrm{NaCl}+\mathrm{H}_{2} \mathrm{O}+\mathrm{NH}_{3}+\mathrm{CO}_{2} \rightarrow \mathrm{NaHCO}_{3}+\mathrm{NH}_{4} \mathrm{Cl}\)

\(\displaystyle \mathrm{Ca}(\mathrm{OH})_{2}+\mathrm{Cl}_{2} \rightarrow \mathrm{CaOCl}_{2}+\mathrm{H}_{2} \mathrm{O}\) /

\(\displaystyle 2 \mathrm{Ca}(\mathrm{OH})_{2}+2 \mathrm{Cl}_{2} \rightarrow \mathrm{Ca}(\mathrm{ClO})_{2}+\mathrm{CaCl}_{2}+2 \mathrm{H}_{2} \mathrm{O}\)

\(\displaystyle \mathrm{CaSO}_{4} \cdot 2 \mathrm{H}_{2} \mathrm{O} \xrightarrow{373 \mathrm{~K}} \mathrm{CaSO}_{4} \cdot \frac{1}{2} \mathrm{H}_{2} \mathrm{O}+1 \frac{1}{2} \mathrm{H}_{2} \mathrm{O}\)