The relative energies (kJ/mol) of the stationary points of a reaction R -> I1 -> I2 -> P are: R = 0, TS1 = 55, I1 = 15, TS2 = 85, I2 = 30, TS3 = 50, P = -25. The rate-determining step is

none, because the overall reaction is exothermic

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The relative energies (kJ/mol) of the stationary points of a reaction $R I X_{1} I X_{2} P$ are: R = 0, TS1 = 55, I1 = 15, TS2 = 85, I2 = 30, TS3 = 50, P = $- 25$ . The rate-determining step is

Astep 3 ( $I X_{2} P$ )
Bstep 2 ( $I X_{1} I X_{2}$ )
Cstep 1 ( $R I X_{1}$ )
Dnone, because the overall reaction is exothermic

Answer: B

The highest-energy transition state is TS2 at 85 kJ/mol. Its barrier from I1 is 70 kJ/mol, compared with 55 kJ/mol for step 1 and 20 kJ/mol for step 3. The slowest step is therefore step 2.

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The relative energies (kJ/mol) of the stationary points of a reaction R​IX1​​IX2​​P are: R = 0, TS1 = 55, I1 = 15, TS2 = 85, I2 = 30, TS3 = 50, P = −25. The rate-determining step is

Answer: B

More questions on Reaction energy profiles, kinetic vs thermodynamic control

The relative energies (kJ/mol) of the stationary points of a reaction $R I X_{1} I X_{2} P$ are: R = 0, TS1 = 55, I1 = 15, TS2 = 85, I2 = 30, TS3 = 50, P = $- 25$ . The rate-determining step is