Selected MCQ

Current Question
The mineral calcite reacts vigorously with dilute hydrochloric acid because it is a:
  • A. Silicate
  • B. Sulfide
  • C. Carbonate
  • D. Oxide
Correct Answer: C
Explanation:
Carbonates effervesce by releasing (CO_2) upon acid reaction.
Related Question 1
The common-ion effect suppresses the ionization of a weak acid because it:
  • A. Increases (K_a)
  • B. Shifts equilibrium toward undissociated acid
  • C. Eliminates water autoionization
  • D. Makes the acid strong
Correct Answer: B
Explanation:
Added common ion drives dissociation equilibrium to the left.
Related Question 2
Which factor increases acidity of organic compounds?
  • A. Electron donating groups
  • B. Electron withdrawing groups
  • C. Alkyl substitution
  • D. Decreasing electronegativity
Correct Answer: B
Explanation:
Electron-withdrawing stabilizes conjugate base.
Related Question 3
Which acid is diprotic?
  • A. HCl
  • B. H₂SO₄
  • C. HNO₃
  • D. HF
Correct Answer: B
Explanation:
Sulfuric acid donates two protons.
Related Question 4
Which acid is strongest in water?
  • A. HF
  • B. HClO₄
  • C. H₂CO₃
  • D. CH₃COOH
Correct Answer: B
Explanation:
Perchloric acid fully dissociates.
Related Question 5
Which acid is strong?
  • A. CH₃COOH
  • B. HCl
  • C. H₂CO₃
  • D. HF
Correct Answer: B
Explanation:
HCl fully ionizes.