NEETChemistryChemical Kinetics
For a reaction between reactants X and Y, it is observed that doubling the concentration of X while keeping the concentration of Y constant increases the reaction rate by a factor of 8. Furthermore, halving the concentration of Y while keeping the concentration of X constant reduces the reaction rate to half of its initial value. The overall order of the reaction is
Options
- A2
- B3
- C5
- D4
Correct answer
D. 4
Step-by-step solution
Let the rate law be Rate = k[ X ]^m[ Y ]^n . When the concentration of X is doubled, the rate increases by a factor of 8: 2^m = 8 m = 3 When the concentration of Y is halved, the rate is halved: ( 1 2 )^n = 1 2 n = 1 The overall order of the reaction is the sum of the partial orders: Overall order = m + n = 3 + 1 = 4 . Answer: 4