Understanding Acidic and Basic Salts

Why is the answer Carbonic Acid and not Phosphoric Acid?

Which of the following acids does not form acidic salts?
a) Phosphoric acid
b) Carbonic acid
c) Hydrochloric acid
d) Sulphuric acid

Answer:

Carbon containing acids are weak as they break down and form H+ ions. Let's take Carbonic acid as an example.

When Carbonic acid (H2CO3) dissociates in water, it forms H+ ions and bicarbonate ions (HCO3-). This dissociation process does not lead to the formation of acidic salts.

In contrast, acids like Phosphoric acid can form acidic salts when they react with metals. The formation of acidic salts involves the replacement of hydrogen ions with metal ions, resulting in the formation of salts that can produce acidic solutions.

Therefore, Carbonic acid is the correct answer in this context because it does not form acidic salts like Phosphoric acid.

What is hydrolysis of a salt?

When a salt is dissolved in water, one or more of the ions in the salt react with water. This reaction of the ions of the salt with water is known as hydrolysis of a salt.

Answer:

Hydrolysis of a salt involves the reaction of the ions of the salt with water when the salt is dissolved in water.

For instance, when a salt like MHCO3 (where M is a metal) undergoes hydrolysis, it produces bicarbonate ions (HCO3-) which are basic in nature. This reaction results in the formation of a basic solution.

Carbonic acid, being a weak acid, cannot form acidic salts but can yield basic ions through hydrolysis of its salts. This further emphasizes the difference between acid salts and the products of salt hydrolysis.