Question

A compound X of sodium forms a white powder. It is a constituent of baking powder and used in some antacids.When heated it gives compound Y which is anhydrous and absorbs water to become hydrated salt . When kept open in air, Y looses water molecules in a process called efflorescence.When dissolved in water it forms a strong base and weak acid Z.

i)What is Y?
ii)What is the nature of the solution formed by dissolving Y in water?
iii)Identify Z.​

Answer 1

Answer:

Y is sodium carbonate

as y is basic in nature so it will form basic solution.

Z is Sodium Hydroxide

Answer 2

The answers to the above questions are given below:

(i) Y is sodium carbonate.

(ii) The nature of the solution formed by dissolving Y in water is alkaline.

(iii) Z is carbonic acid.

• Sodium bicarbonate (NaHCO3) is a white crystalline compound that is a constituent of baking powder. It is used as antacids and in fire extinguishers.
• When sodium bicarbonate is heated, it forms sodium carbonate (Na2CO3) and water with the release of carbon dioxide.
• Hence, Y is sodium carbonate.
• When Y absorbs water, it is converted into sodium carbonate decahydrate (Na2CO3. 10H2O) which is a hydrated salt and the most common form of sodium carbonate.
• When sodium carbonate crystal is kept open in the air, it loses nine water molecules and is converted into sodium carbonate monohydrate (Na2CO3. H2O). This process is called efflorescence.
• When Y or sodium carbonate is dissolved in water, it forms a solution having weak acid, carbonic acid and a strong base, sodium hydroxide. This solution is alkaline in nature.