(i) → (c)

Calcium carbonate used in manufacturing high quality paper because the paper and cardboard industries use lime-based coating pigments and filters such as GCC(Ground Calcium Carbonate). GCC is made from concentrated and fine-ground calcium carbonate and used to make fine paper, cardboard packaging and pulp-based paper.

(ii) → (d)

Calcium Hydroxide is used in white washing because for white washing walls as it slowly reacts with CO₂in air to form a thin layer of Calcium Carbonate on the walls. The layer of Calcium Carbonate gives a shiny finish to the walls.

Ca(OH)₂ + CO₂→ CaCO₃ + H₂O

(iii) → (b)

CaO is used in manufacturing of sodium carbonate from caustic soda.

Above process is also known as Solvay Process. This reaction occurs in two steps.

First step,

NaCl + CO₂ + NH₃ + H₂O → NaHCO₃ + NH₄Cl(l)

First Ammonia converts into Sodium Hydrogen Carbonate and Ammonium Chloride.

Second Step,

2NaCl + CaCO₃→ Na₂CO₃ + CaCl₂

So, in the next or second step, there is the formation of Sodium Carbonate.

(iv) → (a)

CaSO₄ is used in Dentistry, Ornamental work because CaSO₄with adequate quantity of water, it forms a plastic mass that sets into a hard solid.