Which of the following statements is true about $\mathrm{Ca}{\left(\mathrm{OH}\right)}_{2}$?

1. It is used in the preparation of bleaching powder

2. It is a light blue solid

3. It does not possess a disinfectant property

4. It is used in the manufacture of cement

Hint: Ca(OH)2 is white in colour

Calcium hydroxide is used in the manufacture of bleaching powder.
$\underset{\mathrm{Slaked}\phantom{\rule{0ex}{0ex}}\mathrm{lime}}{2\mathrm{Ca}{\left(\mathrm{OH}\right)}_{2}}+2{\mathrm{Cl}}_{2}\stackrel{\mathrm{Cold}}{\to }{\mathrm{CaCl}}_{2}+\underset{\mathrm{Bleacing}\phantom{\rule{0ex}{0ex}}\mathrm{powder}}{\mathrm{Ca}{\left(\mathrm{OCl}\right)}_{2}}+2{\mathrm{H}}_{2}\mathrm{O}$