Question

Lime water reacts with chlorine to form

• A. ${\mathrm{CaCl}}_2$
• B. ${\mathrm{CaOCl}}_2$
• C. $\mathrm{Ca}{\left({\mathrm{ClO}}_3\right)}_2$
• D. ${\mathrm{CaO}}_2{\mathrm{Cl}}_2$

Answer 1

The correct option is B

${\mathrm{CaOCl}}_2$

The explanation for the correct option:

Option (B): ${\mathrm{CaOCl}}_2$

1. A saturated aqueous solution of calcium hydroxide is known as limewater with the chemical formula $\mathrm{Ca}{\left(\mathrm{OH}\right)}_2$
2. ${\mathrm{CaOCl}}_2$, also known as bleaching powder, is formed when lime water combines with chlorine. $\underset{\mathrm{Calcium}\mathrm{Hydroxide}}{2\mathrm{Ca}{\left(\mathrm{OH}\right)}_2\left(\mathrm{aq}\right)}+\underset{\mathrm{Chlorine}}{2{\mathrm{Cl}}_2\left(\mathrm{g}\right)}\to \underset{\mathrm{Calcium}\mathrm{hypochlorite}}{\mathrm{Ca}{\mathrm{OCl}}_2\left(\mathrm{s}\right)}+\underset{\mathrm{Calcium}\mathrm{chloride}}{{\mathrm{CaCl}}_2\left(\mathrm{s}\right)}+\underset{\mathrm{Water}}{2{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)}$
3. Bleaching powder is an inorganic compound. Although the compound is soluble in water, the solution obtained by combining it with water is not clear due to the presence of contaminants.
4. Calcium hypochlorite gives a strong smell of chlorine when kept open.
5. Hence, it is the correct option.

Therefore, ${\mathrm{CaOCl}}_2$ is formed when lime water reacts with chlorine. Hence option (B) is the correct answer.