Usually, chemical processes require an optimum pH. This is the pH at which the desired chemical conversion gives the maximum yield.
As we can see, the pH of the system is much higher than the optimum pH. We can decrease the pH to the optimum pH of 5.0 by adding an appropriate amount of a base such as NaOH.
Hence, the pH can be brought to 5.0 from 6.5 by adding an appropriate amount of NaOH.
Torrey's neighbour is incorrect because increase in kinetic energy is proportional to velocity. If the velocity increases so will the object's kinetic energy. Because the mass is constant, if the velocity increases, so does the kinetic energy.