Practice Problem 2
Calculate the rate constant for the reaction between phenolphthalein and the OH- ion if the instantaneous rate of reaction is 2.5 x 10-5 mole per liter per second when the concentration of phenolphthalein is 0.0025 M.
We start with the rate law for this reaction:
Rate = k(phenolphthalein)
We then substitute the known rate of reaction and the known concentration of phenolphthalein into this equation:
Solving for the rate constant gives the following result:
k = 0.010 s-1