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Identify the correct statement(s) among the following: (P) A catalyst does not change the enthalpy change (delta H) of a reaction. (Q) Increasing the concentration of a reactant always increases the rate of reaction. (R) An increase in temperature raises the rate of reaction mainly because of the increase in collision frequency among reactant molecules.
- Only P
- Only Q
- Only R
- None of these
Correct answer: Only P
Solution
P is correct: a catalyst affects kinetics, not thermodynamics. Q is false for zero-order reactions. R is false: the dominant effect of temperature is the increase in the fraction of molecules exceeding the activation energy (Boltzmann factor), not collision frequency.
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