Answer
Adding an equal volume of pure ethyl alcohol would result in a reaction rate that is 0.25 times the original rate.
Work Step by Step
Adding an equal volume of the solvent translates to multiplying the original solvent value by two.
Increasing the volume of the solvent by a factor of 2 decreases the concentration of the two reactants by a factor of 0.5 according to the concentration equation: M = (moles solute)/(L of solvent)
Use the rate law to determine the overall change in reaction rate:
k[C2H5Br][OH]
k[0.5 * C2H5Br][0.5 * OH] = 0.25(k[C2H5Br][OH])
