Question

Which of the following statements are true about ${ Ca(OH) }_{ 2 }$?
(A) It is used in the preparation of bleaching powder.
(B) It is a light blue solid.
(C) It does not possess disinfectant property.
(D) It is used in the manufacturer of cement.

Answer 1

Hint: Slaked lime ${ Ca(OH) }_{ 2 }$ is a white amorphous powder of calcium hydroxide. It is a colorless crystal or white powder and is sparingly soluble in water.

Complete step-by-step answer:
${ Ca(OH) }_{ 2 }$: It is prepared when quick lime is mixed with water.
A. Bleaching powder can be prepared when dry slaked lime is treated with chlorine gas. The following reaction will take place:

${ 2Ca(OH) }_{ 2 }{ +2Cl }_{ 2 }{ \rightarrow CaCl }_{ 2 }{ +Ca(OCl) }_{ 2 }{ +2H }_{ 2 }{ O }$

Hence, ${ Ca(OH) }_{ 2 }$ is used in the preparation of bleaching powder.
B. Slaked lime is a whitish colored powder not a light blue solid. So, this statement is incorrect.
C. Disinfectants are meant to destroy microorganisms that can infect non-living objects. These are commonly used on household items to protect germs and colds from spreading to people. Slaked lime possesses the disinfectant property.
D. Slaked lime is made from quicklime and water. Quicklime can be used in the manufacture of cement, hence slaked lime can be used in the manufacturer of cement as well. So, this statement is true.

The correct answer is A and D.

Note: The possibility to make a mistake is that you may not choose option D. As we know slaked lime is used in the preparation of bleaching powder but it is also used in the manufacture of cement.