Question

Explain why an aqueous solution of ammonium chloride is acidic in nature.

Answer 1

Hint: Before proceeding to the question let us first have a basic knowledge of ammonium chloride. The inorganic compound ammonium chloride $ \left( {N{H_4}Cl} \right) $ is a white crystalline salt that is extremely soluble in water. Ammonium chloride solutions are moderately acidic.

Complete answer:
Because ammonium chloride $ \left( {N{H_4}Cl} \right) $ is the salt of a strong acid, hydrochloric acid $ (HCl) $ , and a weak base, ammonium hydroxide $ \left( {N{H_4}OH} \right) $ , its aqueous solution is acidic.
Explanation:-
We'll look at how acidic it is in aqueous solution.
The ionisation of $ \left( {N{H_4}Cl} \right) $ produces the $ NH_4^ + $ ion and the $ C{l^ - } $ ion. These ions react with the water molecule's $ {H^ + } $ and $ O{H^ - } $ ions to generate $ N{H_4}OH $ and $ HCl $ , respectively.
 $ N{H_4}Cl \to N{H_4} + C{l^ - } $
 $ N{H_4}OH \Leftrightarrow N{H_4} + O{H^ - } $
 $ HCl \to {H^ + } + C{l^ - } $
As demonstrated above, the $ HCl $ molecule will completely ionise to generate the $ {H^ + } $ ion.
However, as illustrated above, the $ N{H_4}OH $ molecule only partially ionises. As a result, the ions present in the $ \left( {N{H_4}Cl} \right) $ solution will be $ NH_4^ + $ , $ C{l^ - } $ , $ {H^ + } $ , and $ O{H^ - } $ . Aside from this, there will be some $ N{H_4}OH $ that is unionised.
As previously stated, the quantity of $ {H^ + } $ ions will exceed the number of $ O{H^ - } $ ions. As a result, the $ \left( {N{H_4}Cl} \right) $ Solution will be acidic.

Additional Information:
Ammonium chloride is most commonly used as a nitrogen source in fertilisers, such as chloro ammonium phosphate (which accounts for $ 90\% $ of global ammonium chloride production). Rice and wheat are the most common crops fed this manner throughout Asia.

Note:
Sal Ammoniac, commonly known as sal ammoniac or salmiak, is a rare naturally occurring mineral made up of ammonium chloride. In the isometric-hexoctahedral class, it produces colourless, white, or yellow-brown crystals. It has poor cleavage and is brittle enough to fracture conchoidally. It's a water-soluble substance. The chemical compound ammonium chloride is also known as sal ammoniac.