Question

Calcium hydroxide $Ca{(OH)_2}$ in water is used for:
A.White washing
B.Preparing ammonia, caustic soda and bleaching powder
C.Reducing the activities of the soil
D.All of the above purposes

Answer 1

Hint:Firstly we have to take the question part by part due to the commercial nature of the compound. Now the calcium hydroxide $Ca{(OH)_2}$ is used for white washig and it is a wide commercial use for the compound. Apart from that we also have the characterisy-tic equations for the $Ca{(OH)_2}$ that gives all the products. And it is also used to make soil basic.

Complete step by step answer:
The given question should be addressed step by step in which we will address all the given options in each of the given steps so we can find out the correct option for it.
Step 1: The first option is the white washing.
It is well known that calcium hydroxide is a well integral and principal ingredient when used for the whitewash. The plaster and the mortar are also prepared using it. Therefore we can say that the first option is indeed the correct one.
Step 2: The second option is Preparing ammonia, caustic soda and bleaching powder.
There are some principal reactions which are given by the calcium hydroxide.
\[ 2N{H_4}Cl + Ca{(OH)_2} \to CaC{l_2} + 2N{H_3} \uparrow + 2{H_2}O \\
  Na{_2}C{O_3} + Ca{(OH)_2} \to CaC{O_3} + 2NaOH \\
  C{l_2} + Ca{(OH)_2} \to CaOC{l_2} + {H_2}O \\
\]
Therefore this option is correct too.
Step 3: The option is to reduce the activities of the soil.
We know that calcium hydroxide is a well used base for commercial purposes. It is also used in the soil when the soil indeed becomes acidic in nature. This makes the soil both neutral and well nutritioned
So this option is correct too.

Therefore the correct option would be D, all of the above.

Note:Calcium hydroxide is an inorganic compound. It is a colorless crystal or white powder and is produced when quicklime (calcium oxide) is mixed, or slaked with water. It has many names including hydrated lime, caustic lime, builders' lime, slack lime, cal, or pickling lime. Its most common name is slaked lime.