The `pH` of an acidic buffer can be raised by `2`units by

Options

A. Increasing the concentration of both weak acid and salt by two moles
B. Increasing the concentration of both the acid and salt by `10` times.
C. Diluting the solution by `10` times.
D. Increasing the concentration of the salt by `10` times by decreasing concentration of the acid by `10` times.

Answer

D

Explanation

`pH_(1) = pK_(a) +log (("Salt")/("Acid"))`
`pH_(1) = pK_(a) + log ((x_(1))/(y_(1)))`
`pH_(2) = pK_(a) + log ((x_(2))/(y_(2)))`
`pH_(2) - pH_(1) = "log"(x_(2))/(y_(2)) -"log"(x_(1))/(y_(1))`
`2 = log ((x_(2)//y_(2))/(x_(1)//y_(1)))`
`:. (x_(2)//y_(2))/(x_(1)//y_(1)) = 10^(2) = 100`
This is only possible, if the concentration of salt is increased by `10` times and the concentration of acid is decreased by `10` times.