Question

Match the important chemicals given in Column (A) with the chemical formulae given in Column (B)

Column 1	Column 2
Plaster of Paris	$\mathrm{Ca}{\left(\mathrm{OH}\right)}_2$
Gypsum	${\mathrm{CaSO}}_4.1/2{\mathrm{H}}_2\mathrm{O}$
Bleaching powder	${\mathrm{CaSO}}_4.2{\mathrm{H}}_2\mathrm{O}$
Slaked Lime	${\mathrm{CaOCl}}_2$

Answer 1

(A) Plaster of Paris- II)${\mathbf{CaSO}}_{\mathbf{4}}\mathbf{.}\mathbf{1}\mathbf{/}\mathbf{2}{\mathbf{H}}_{\mathbf{2}}\mathbf{O}$

1. Plaster of Paris is also referred to as Gypsum Plaster.
2. Its chemical formula is ${\mathrm{CaSO}}_4.1/2{\mathrm{H}}_2\mathrm{O}$.

(B) Gypsum-III) ${\mathbf{CaSO}}_{\mathbf{4}}\mathbf{.}\mathbf{2}{\mathbf{H}}_{\mathbf{2}}\mathbf{O}$

1. Gypsum is a soft sulfate mineral composed of calcium hydrate sulfate dihydrate as the main constituent in many forms of plaster, blackboard or sidewalk chalk.
2. Gypsum has a chemical formula ${\mathrm{CaSO}}_4.2{\mathrm{H}}_2\mathrm{O}$.

(C) Bleaching Powder- IV) ${\mathbf{CaOCl}}_{\mathbf{2}}$

1. Bleaching powder is a white powder that decomposes on contact with water and has the characteristic odour of gaseous chlorine.
2. Its chemical formula is ${\mathrm{CaOCl}}_2$.

(D) Slaked Lime- I) $\mathbf{Ca}{\mathbf{\left(}\mathbf{OH}\mathbf{\right)}}_{\mathbf{2}}$

1. It is a colourless crystal or white powder and is produced when quicklime is mixed with or slaked with water.
2. Its chemical formula is $\mathrm{Ca}{\left(\mathrm{OH}\right)}_2$.

Therefore:

Important chemicals	Formula
(A) Plaster of Paris	2.${\mathrm{CaSO}}_4.1/2{\mathrm{H}}_2\mathrm{O}$
(B) Gypsum	3.${\mathrm{CaSO}}_4.2{\mathrm{H}}_2\mathrm{O}$
(C) Bleaching Powder	4.${\mathrm{CaOCl}}_2$
(D) Slaked lime	1.$\mathrm{Ca}{\left(\mathrm{OH}\right)}_2$