NEET Chemistry: Acids and Bases questions with solutions

Q1. The strength of an acid refers to its ability or tendency to lose a:

1. electron
2. proton
3. neutron
4. none of above

Answer: proton

An acid is defined by its tendency to donate a proton (H+). The stronger the acid, the more easily it loses that proton in solution.

Q2. 100ml of a solution of HCl with pH value 3 is diluted with \( 400 \mathrm{ml} \) of water. The new pH of the solution is?

1. 3.7
2. 5.3
3. 4.2
4. 5.6

Answer: 3.7

When the acidic solution is diluted, the pH increases, as the concentration of hydrogen ions decreases. The new pH can be calculated using the dilution formula. [AI-generated key — verify before high-stakes use]

Q3. In the reaction, \( \boldsymbol{H}_{2} \boldsymbol{P} \boldsymbol{O}_{4}^{-}+\boldsymbol{H}_{2} \boldsymbol{O}(l)= \) \( \boldsymbol{H}_{3} \boldsymbol{O}^{+}(\boldsymbol{l})+\boldsymbol{H} \boldsymbol{P} \boldsymbol{O}_{4}^{2-}(l) \) the hydrogen phosphate ion is the:

1. bronsted acid
2. bronsted base
3. conjugate acid
4. conjugate base

Answer: conjugate base

H2PO4− transfers a proton to water, so it acts as an acid in the forward reaction. After losing H+, it becomes HPO4^2−, which is the conjugate base of H2PO4−.

Q4. Antacids are

1. acidic
2. basic
3. salt
4. ionic

Answer: basic

Antacids are substances that neutralize gastric acid, so they must be alkaline rather than acidic. Therefore, they are basic.

Q5. Which of the following exhibits different colors in acidic and basic solutions?

1. Buffer
2. Indicator
3. Arrhenius acid
4. Arrhenius base E. Neutral condition

Answer: Indicator

An indicator is designed to show different colors in acidic and basic environments, so it can reveal the pH of a solution. Buffers, Arrhenius acids, Arrhenius bases, and neutral conditions do not have this color-changing property.

Q6. A solution contains \( 10 \mathrm{mL} \) of \( 0.1 \mathrm{N} \) NaOH and \( 10 \mathrm{mL} \) of \( 0.05 \mathrm{Na}_{2} \mathrm{SO}_{4} . \) pH of this solution is

1. equal to 7
2. less than 7
3. greater than 7
4. zero

Answer: greater than 7

NaOH is a strong base, so its hydroxide ions remain in solution and make the mixture alkaline. Sodium sulfate is essentially a neutral salt in this context and does not cancel the base, so the final pH is above 7.