COMEDK202510 May 2025Evening ShiftChemistryChemical KineticsActual
Which one of the following is incorrect?
Options
- ALarger the value of rate constant ( k ) value faster is the chemical reaction.
- BThe unit for rate constant for n ^ th order reaction is ( mol L ⁻¹ )^ n -1 ~s ⁻¹
- CRate constant equals the rate of reaction when concentration of reactants equals unity.
- DThe value of rate constant (k) is independent of concentration of reactants.
Correct answer
B. The unit for rate constant for n ^ th order reaction is ( mol L ⁻¹ )^ n -1 ~s ⁻¹
Step-by-step solution
For an n^ th order reaction: Rate = k[ Reactant ]^n Unit of k = mol L⁻¹ s⁻¹ ( mol L⁻¹)^n = ( mol L⁻¹)^ 1-n s⁻¹ Option (2) states the exponent as (n-1) instead of the correct (1-n) , making it incorrect. (1) Correct: Larger k means faster reaction by the rate law. (3) Correct: When [ Reactant ] = 1 , Rate = k(1)^n = k . (4) Correct: k depends on temperature and activation energy, not on concentration. The incorrect statement is (2).