Question 8 - Case Based Questions (MCQ) - Chapter 2 Class 10 - Acids, Bases and Salts

Sanjana while preparing cake used baking soda in  small amounts. It helps to make the cake soft and  spongy. An aqueous solution of baking soda also  turns red litmus blue. It is also used in soda acid  extinguishers.

(a) Name the gas produced by the reaction of baking soda and acid which helps as fire extinguisher: 

(i) Carbon monoxide 

(ii) Carbon dioxide  

(iii) Hydrogen 

(iv) Oxygen  

Ans. 

Baking soda i.e. sodium bicarbonate (NaHCO ₃ ) is basic in nature. 

It reacts with an acid as follows:

In the reaction, CO ₂ gas is released which helps in extinguishing fire.

So, the correct option is (ii) 

(b) Name the products formed when baking soda is  heated:  

(i) sodium sulphate and carbon dioxide gas  

(ii) sodium carbonate and water  

(iii) sodium carbonate, carbon dioxide and water.  

(iv) Sodium oxide, carbon dioxide and water.

Ans. 

When baking soda is heated, following reaction takes place:

Thus, the products formed are

• Sodium Carbonate
• Carbon Dioxide
• Water

So, the correct answer is (iii) 

(c) The pH of baking soda solution is:  

(i) more than 7  

(ii) less than 7  

(iii) equal to 7  

(iv) less than 7 but more than 3. 

Ans. 

Since baking soda is basic in nature , its solution will have a pH more the 7

So, the correct answer is (i)

(d) What is the chemical name for baking soda?  

(i) Sodium carbonate  

(ii) sodium bicarbonate  

(iii) calcium carbonate  

(iv) calcium bicarbonate. 

Ans. 

The chemical name for baking soda is sodium bicarbonate (NaHCO ₃ )

So, the correct answer is (ii)