Question

Calcium hydroxide is also known as:
A. limestone
B. slaked lime
C. quick lime
D. washing soda

Answer 1

Hint: Calcium hydroxide has a molecular formula of $\text{Ca(OH}{{\text{)}}_{2}}$ and also known as hydrated lime and pickling lime. The powder of calcium hydroxide is white coloured which is used in plasters, cement, etc. It is made from quicklime that is calcium oxide.

Complete answer:
- In the given question, we have to explain the correct term used for the calcium hydroxide.
- As we know that calcium hydroxide has a molecular formula of $\text{Ca(OH}{{\text{)}}_{2}}$ which is a white powder.
- This compound has many alternative names such as hydrated lime or pickling lime or caustic lime or slaked lime.
- The formation of calcium hydroxide takes place by the reaction between calcium hydroxide and water i.e.
$\text{CaO + }{{\text{H}}_{2}}\text{O }\to \text{ Ca(OH}{{\text{)}}_{2}}$
- Here, calcium oxide is also known as quicklime which combines with water to form slaked lime
- Whereas calcium oxide or quick lime is formed from the limestone that is calcium carbonate by the heating process.
$\text{CaC}{{\text{O}}_{3}}\text{ }\xrightarrow{\vartriangle }\text{ CaO + C}{{\text{O}}_{2}}$
- The formation of quicklime from limestone and slaked lime from quicklime is known as the lime cycle.
- Now, the formula of washing soda or sodium carbonate is $\text{N}{{\text{a}}_{2}}\text{C}{{\text{O}}_{3}}$.
- Washing soda is most commonly used in the laundry as a detergent and to soften the hard water as it is not easy to wash the clothes in the hard water.

Therefore, option B is the correct answer.

Note:
Slaked lime gives hydroxide ion when dissolved in the water so it is considered as a base and used in the treatment of the waste products, fillings that are used in the root canal and also used in the manufacturing of paper.