Most Important MCQs on the topic: Acid and Base for the competitive exam:

1. Which of the following is a characteristic of acids?

   a) Slippery to touch  

   b) Turns blue litmus paper red  

   c) Has a pH greater than 7  

   d) Bitter in taste  

   👻 Answer: b) Turns blue litmus paper red

2. Which of the following is an example of a strong acid?

   a) Acetic acid  

   b) Hydrochloric acid  

   c) Citric acid  

   d) Carbonic acid  

   👻 Answer: b) Hydrochloric acid

3. What is the pH value of pure water at 25°C?

   a) 3  

   b) 5  

   c) 7  

   d) 9  

   👻 Answer: c) 7

4. Which substance can act as both an acid and a base?

   a) NaOH  

   b) HCl  

   c) \(H_2O \) 

   d) \(CH_3COOH  \) 

   👻 Answer: c) \(H_2O\) 

5. Which of the following is a property of a base?

   a) Sour taste  

   b) Turns red litmus paper blue  

   c) Reacts with metals to produce hydrogen gas  

   d) Has a pH less than 7  

   👻 Answer: b) Turns red litmus paper blue

6. The pH of an acidic solution is generally:

   a) Less than 7  

   b) More than 7  

   c) Equal to 7  

   d) Cannot be determined  

   👻 Answer: a) Less than 7

7. Which of the following is a weak base?

   a) Sodium hydroxide  

   b) Ammonium hydroxide  

   c) Potassium hydroxide  

   d) Calcium hydroxide  

   👻Answer: b) Ammonium hydroxide

8. Which of the following ions is responsible for the acidity of a solution?

   a) OH⁻ ions  

   b) Na⁺ ions  

   c) H⁺ ions  

   d) Cl⁻ ions  

   👻 Answer: c) H⁺ ions

9. What happens when an acid reacts with a base?

   a) A salt and water are formed  

   b) Only water is formed  

   c) A gas is released  

   d) The solution becomes neutral  

   👻 Answer: a) A salt and water are formed

10. The reaction between an acid and a base is called:

    a) Sublimation  

    b) Neutralisation  

    c) Precipitation  

    d) Oxidation  

    👻Answer: b) Neutralisation

These questions cover fundamental concepts of acids, bases, and their reactions.