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Very Short Question and Answers - Salts

Q 1.
What is the common name of the compound CaOCl₂?

Ans:

The common name of CaOCl₂ is Bleaching Powder.

Q 2.
Name the substance which, on treatment with chlorine, yields bleaching powder.

Ans:

The substance is dry slaked lime (Ca(OH)₂).

Q 3.
Name the sodium compound which is used for softening hard water.

Ans:

The sodium compound used for softening hard water is Sodium Carbonate (Na₂CO₃).

Q 4.
What will happen if a solution of sodium hydrogencarbonate is heated? Give the equation of the reaction involved.

Ans:

When sodium hydrogencarbonate (NaHCO₃) is heated, it decomposes to form sodium carbonate, water, and carbon dioxide: 2NaHCO₃ → Na₂CO₃ + H₂O + CO₂.

Q 5.
Write an equation to show the reaction between Plaster of Paris and water.

Ans:

The reaction is: CaSO₄·(1/2)H₂O + H₂O → CaSO₄·2H₂O.

Q 6.
What are salts formed from?

Ans:

Salts are formed from the reaction between an acid and a base.

Q 7.
Identify the acid that reacts with sodium hydroxide to form sodium chloride.

Ans:

The acid is Hydrochloric acid (HCl).

Q 8.
What happens to the color of copper sulphate crystals upon heating?

Ans:

The color changes from blue to white upon heating due to loss of water of crystallisation.

Q 9.
What is the pH of salts formed from strong acids and strong bases?

Ans:

The pH of these salts is neutral, at a value of 7.

Q 10.
What is the role of sodium chloride in the manufacture of sodium hydroxide?

Ans:

Sodium chloride is used as raw material in the chlor-alkali process to produce sodium hydroxide.

Q 11.
What is the main use of baking soda?

Ans:

Baking soda (sodium hydrogencarbonate) is used in cooking and baking as a leavening agent.

Q 12.
Which salt is used as an antacid?

Ans:

Sodium hydrogencarbonate (baking soda) is used as an antacid.

Q 13.
What is the chemical formula of sodium bicarbonate?

Ans:

The chemical formula of sodium bicarbonate is NaHCO₃.

Q 14.
What is the chemical formula for washing soda?

Ans:

The chemical formula for washing soda is Na₂CO₃·10H₂O.

Q 15.
What do we call salts that have the same positive or negative radicals?

Ans:

They are called a family of salts.

Q 16.
What is the process through which sodium hydroxide is produced from brine?

Ans:

The process is called the chlor-alkali process.

Q 17.
How does the pH of sodium acetate compare to that of sodium chloride?

Ans:

Sodium acetate is basic, usually above pH 7, while sodium chloride is neutral with a pH of 7.

Q 18.
What happens to copper sulphate when water is added after heating?

Ans:

The blue color of copper sulphate is restored when water is added.

Q 19.
What signifies water of crystallisation?

Ans:

It signifies the fixed number of water molecules present in one formula unit of a salt.

Q 20.
What is Plaster of Paris formed from?

Ans:

Plaster of Paris is formed by heating gypsum (CaSO₄·2H₂O) at 373 K.

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