Question

An alkali used for removing grease stain is:
(a)- $HCl$
(b)- $Al{{(OH)}_{3}}$
(c)- $N{{H}_{4}}OH$
(d)- $N{{a}_{2}}S{{O}_{4}}$

Answer 1

Hint: The alkali that is used for removing the grease stain will give hydroxyl ion on hydrolysis. It is basic in nature. The fumes of this compound are very irritating.

Complete step by step answer:
An alkali is a substance which is basic in nature. A base is that substance that has a hydroxyl group ($O{{H}^{-}}$) and when the substance is dissolved in water it dissociates into a cation and hydroxyl ion.
So, the alkalis are those bases that are soluble in water. So, the alkali that is used for cleaning the greasy stains of utensils, windows, ovens, etc is Ammonium hydroxide having formula $N{{H}_{4}}OH$.
Ammonium hydroxide is also known as ammonia water, ammonia solution, aqua ammonia, etc. The solution that is used for cleaning purposes has a very low amount of ammonia i.e., 1-3% of ammonia in the solution. As the ammonia is a gas and ammonia solution means gas dissolved in liquid, so as the liquid evaporates the ammonia also evaporates leaving the window streak-free. Commercially it is sold in three forms: plain, lemon-scented which is typically a yellow colored solution, and pine-scented which is the green-colored solution. Cloudy ammonia is a soap that contains a little amount of ammonia.
So, the correct answer is “Option C”.

Note: The fumes of ammonium hydroxide are very irritating to the eyes. It is also used in water treatment, aquarists, food production, furniture darkening, treatment of straw for cattle, etc. and in chemistry is used for making primary amines.