Determining Rate Constant for Hydrolysis of Ethyl Lactate with Acid Catalysis?

[sarahrpol]

Homework Statement

Hydrolysis of ethyl lactate

Determine the value of the rate constant for the hydrolysis of ethyl lactate from the following data.

Mass of ethyl lactate (grams): 0.5956
Concentration of stock HCl solution (M): 0.01023

Standardization titration volumes (of NaOH):

Run Vi (mL) Vf(mL)
1 0.60 15.58
2 15.58 30.66
3 30.66 45.66

Kinetics data:
Run Reaction time (seconds) Vi(mL) Vf(mL)
0 0
1 308 1.72 4.32
2 742 4.32 8.88
3 1303 8.88 14.84
4 1910 14.84 21.66
5 2550 21.66 29.06

Rate constant = ?

Homework Equations

equations are below

The Attempt at a Solution

the rate equation is -d[OH-]/dt = k[OH-][EtL]

but I'm not sure how to find the concentration of OH and the concentration of Ethyl lactate is 0.01203

and then a = 1/2[OH-]o + [Etl]o
1/a-x - 1/a = kt

 

[Borek]

What are the titrations for? What do they determine?

OH^- is just a catalyst and its concentration doesn't change during the hydrolysis, so your rate equation can't be right.

 

[epenguin]

This is really not set out clearly enough to understand or help with.
What are V_i, V_f? What is measured how?
Is this acid catalysis?