Study the roadmap for preparation of washing soda and choose the correcct option:

Washing soda has a chemical name sodium carbonate (${\mathrm{Na}}_2{\mathrm{CO}}_3$). It is prepared mainly by using calcium carbonate. Thus the raw reactant 'P' is calcium carbonate (${\mathrm{CaCO}}_3$)

On heating Calcium carbonate decompose into calcium oxide and carbon dioxide. Thus 'Q' is calcium oxide.

${\mathrm{CaCO}}_3\to \mathrm{CaO}+{\mathrm{CO}}_2$
CaO reacts with water to give calcium hydroxide. So, 'R' is $\mathrm{Ca}{\left(\mathrm{OH}\right)}_2$.

$\mathrm{CaO}\stackrel{{\mathrm{H}}_2\mathrm{O}}{\to }\mathrm{Ca}{\left(\mathrm{OH}\right)}_2$
Calcium hydroxide reacts with ammonium chloride to produce 'S' as ammonia, a gas soluble in water.
$\mathrm{Ca}{\left(\mathrm{OH}\right)}_2+{\mathrm{NH}}_4\mathrm{Cl}\to {\mathrm{NH}}_3+{\mathrm{CaCl}}_2+{\mathrm{H}}_2\mathrm{O}$

This ammonia on treating with carbon dioxide gives 'T' as ammonium bicarbonate. On further reaction with NaCl, sodium bicarbonate is produced. On heating sodium carbonate is yielded as product.

${\mathrm{NH}}_3\stackrel{{\mathrm{CO}}_2}{\to }{\mathrm{NH}}_4{\mathrm{HCO}}_3\stackrel{\mathrm{NaCl}}{\to }{\mathrm{NaHCO}}_3\stackrel{∆}{\to }{\mathrm{Na}}_2{\mathrm{CO}}_3$

Therefore the correct order of species is;

$\begin{array}{rcl} & & \mathrm{P}-{\mathrm{CaCO}}_{\mathrm{3}},\mathrm{Q-}\mathrm{Cao},\mathrm{R-}\mathrm{Ca}{\left(\mathrm{OH}\right)}_{\mathrm{2}}, \\ & & \mathrm{S-}{\mathrm{NH}}_{\mathrm{3}},\mathrm{T-}{\mathrm{NH}}_{\mathrm{4}}\mathrm{OH},\mathrm{U-}{\mathrm{NH}}_{\mathrm{4}}{\mathrm{CO}}_{\mathrm{3}},\mathrm{V-}{\mathrm{NaHCO}}_{\mathrm{3}}\end{array}$

Hence, the correct option is (D).