Selected MCQ

Current Question
Which factor increases reaction rate?
  • A. Lower temperature
  • B. Higher activation energy
  • C. Catalyst
  • D. Decreasing concentration
Correct Answer: C
Explanation:
Catalyst lowers activation energy.
Related Question 1
Which factor increases weathering rate?
  • A. Low temperature
  • B. High rainfall
  • C. Lack of vegetation
  • D. Dry climate
Correct Answer: B
Explanation:
Water accelerates chemical weathering.
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 hormone increases heart rate?
  • A. Insulin
  • B. Adrenaline
  • C. Thyroxine
  • D. Estrogen
Correct Answer: B
Explanation:
Adrenaline stimulates cardiac activity.
Related Question 4
The rate law for a reaction must be determined by:
  • A. Stoichiometry
  • B. Experiment
  • C. Thermodynamics
  • D. Equilibrium constant
Correct Answer: B
Explanation:
Reaction order is experimentally determined.
Related Question 5
In SN1 reactions, the rate-determining step is:
  • A. Nucleophilic attack
  • B. Carbocation formation
  • C. Proton transfer
  • D. Solvent evaporation
Correct Answer: B
Explanation:
SN1 rate depends on unimolecular leaving-group departure to form a carbocation.