Free Acids, Bases and Salts MCQs with Answers
314 Acids, Bases and Salts MCQs from Chemistry, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Acid and base behaviour is explained through the Bronsted-Lowry transfer of protons and the Lewis donation or acceptance of electron pairs. The topic includes pH, pOH, ionisation and water equilibrium, plus salt formation and hydrolysis, where a salt solution may become acidic, basic or neutral.
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Read the Acids, Bases and Salts notesFree MDCAT chapter notes with key terms314 questions · page 3 of 16
- A. NaCl
- B. NaNO₃
- C. KI
- D. All of the above
Explanation: All three salts listed (NaCl, NaNO₃, KI) are formed from the reaction of a strong acid and a strong base.
Correct answer: All of the above- A. NaCl
- B. Na₂CO₃
- C. Na₂SO₄
- D. FeCl₃
Explanation: Sodium carbonate (Na₂CO₃) is the salt of a weak acid (H₂CO₃) and a strong base (NaOH).
Correct answer: Na₂CO₃- A. 14
- B. 10
- C. 12
- D. 13
Explanation: A 10⁻² M NaOH solution has [𝑂𝐻−]=10 −2 So, pOH = 2, and pH = 14 − 2 = 12. Thus, the solution is strongly basic.
Correct answer: 12- A. Addition reaction
- B. Substitution reaction
- C. Neutralization reaction
- D. Reversible reaction
Explanation: A strong acid reacts spontaneously with a strong base. This process produces salt and water and releases energy.
Correct answer: Neutralization reaction- A. 1.34
- B. 3.52
- C. 4.76
- D. 2.53
Explanation: The pK of an acid indicates its strength; lower pK means stronger acid.
Correct answer: 4.7646. 'Ka ' for an acid is higher, the stronger is the acid; relate the strength of an acid with 'pKa ' :
- A. Higher pKa , weaker the acid
- B. Lower pKa , stronger the acid
- C. pKa has no relation with acid strength
- D. Both "Higher pKa , weaker the acid" & "Lower pKa , stronger the acid"
Explanation: The acid dissociation constant Ka measures acid strength; higher Ka means a stronger acid.
Correct answer: Both "Higher pKa , weaker the acid" & "Lower pKa , stronger the acid"- A. 1 M HCl
- B. 1 M HF
- C. 1 M HNO₃
- D. 1 M CH₃COOH
Explanation: A pH of zero corresponds to a hydrogen ion concentration of [H⁺] = 10⁰ = 1 M.
Correct answer: 1 M HCl- A. 10⁻⁵
- B. 10⁻⁹
- C. 10⁵⋅⁵
- D. 10⁻⁷
Explanation: The relationship between pH and pOH is pH + pOH = 14. If the pH is 5, the pOH is 14 - 5 = 9.
Correct answer: 10⁻⁹- A. The HCl solution is less acidic than the HClO₄ solution
- B. The HCl solution is 100 times more acidic than the HClO₄ solution
- C. The HClO₄ solution is 100 times more acidic than the HCl solution
- D. None of these
Explanation: Acidity is determined by the H⁺ concentration. Since both are strong acids, the [H⁺] is equal to their molarity.
Correct answer: The HCl solution is 100 times more acidic than the HClO₄ solution- A. 10⁻⁸·⁵
- B. 10⁸⋅⁵
- C. 8.5
- D. -8.5
Explanation: The pOH of the solution is 14 - pH = 14 - 5.5 = 8.5. The hydroxyl ion concentration is given by [OH⁻] = 10⁻pOH. Therefore, [OH⁻] = 10⁻⁸.⁵ M.
Correct answer: 10⁻⁸·⁵- A. HClO₃
- B. HNO₃
- C. H₂SO₄
- D. HClO₄
Explanation: The highest pKa value corresponds to the weakest acid. Among the given options, nitric acid, sulfuric acid, and perchloric acid are all…
Correct answer: HClO₃- A. Strong base
- B. Strong acid
- C. Neutral
- D. Weak acid
Explanation: The pKa is a measure of acid strength, with lower values indicating stronger acids.
Correct answer: Strong acid- A. Kₐ < 10⁻³
- B. Kₐ=1 to 10⁻³
- C. Kₐ>1
- D. Kₐ= 0
Explanation: A large Ka value means the acid dissociates almost completely, shifting equilibrium far to the right.
Correct answer: Kₐ>1- A. 3
- B. 4
- C. 5
- D. 2
Explanation: A higher pKb value indicates a weaker base. A weaker base corresponds to a stronger conjugate acid and thus a more acidic solution.
Correct answer: 5- A. Strongly basic
- B. Strongly acidic
- C. Basic
- D. Neutral
Explanation: A very large pKb means the base is extremely weak.Its conjugate acid is therefore strong, making the resulting solution strongly acidic.
Correct answer: Strongly acidic- A. Ka=1/Kb
- B. Ka x Kb = Kw
- C. pKw=-logKw
- D. None of these
Explanation: For any conjugate acid-base pair in aqueous solution, the product of their dissociation constants equals the ionproduct constant of water:
Correct answer: Ka x Kb = Kw- A. Add ion reaction
- B. Redox reaction
- C. Elimination reaction
- D. Chain reaction
Explanation: A 'redox reaction' involves the transfer of electrons between substances, leading to changes in oxidation states and electric charges of…
Correct answer: Redox reaction- A. Weak acid and weak base
- B. Weak acid and strong base
- C. Strong acid and strong base
- D. Strong acid and weak base
Explanation: An acidic buffer resists changes in pH and is prepared using a weak acid and its salt.
Correct answer: Weak acid and strong base- A. NH₄⁺
- B. NH
- C. NH₂
- D. NH₂⁻
Explanation: A conjugate acid is formed when a base accepts a proton (H⁺). Ammonia (NH₃) acts as a base and accepts a proton to form NH₄⁺.
Correct answer: NH₄⁺- A. Basic solution
- B. Acidic solution
- C. Neutral solution
- D. None
Explanation: A salt derived from strong acid and weak base will dissolve in water to give a solution which is acidic due to anionic hydrolysis (or) A…
Correct answer: Acidic solution