Question

In a buffer solution consisting of a weak acid and its salt, the rate of the concentration of salt to acid is increased tenfold, then the\[pH\]of the solution will:
A) Increases by one
B) Increases tenfold
C) Decreases by one
D) Decreases tenfold

Answer 1

Hint: Buffer solution may be a water solvent based solution which consists of a mixture containing a weak acid and the conjugate base of the weak acid or weak base. They happen to resist a change in \[pH\] upon the dilution or upon the addition of small amounts of acid/ alkali to them.

Complete answer:
Let us know about buffer solutions. The buffer solution is a solution that can resist changes in $pH$ even when a small amount of acid or alkali are added to it. Generally when acid is added to a buffer, the buffer releases $O{H^ - }$ ions to neutralize the base added to it.
Now let us consider the question,
Using Henderson’s equation,
\[pH = \log \dfrac{{[Salt]}}{{[Acid]}} + p{K_a}\]
$ \Rightarrow $ \[pH = \log 10 + \log \dfrac{{[Salt]}}{{[Acid]}} + p{K_a}\]
$ \Rightarrow $\[pH = 1 + \log \dfrac{{[Salt]}}{{[Acid]}} + p{K_a}\]
The \[pH\] of the solution increases by 1.

Therefore, the option A is correct. i.e. Increase by one.

Additional Information: We must remember that the buffer solution has two types which are discussed below as:

Acidic buffer solution: An acidic buffer solution is nothing but a solution which has a \[pH\] lower than 7. These solutions are evenly made from a weak acid and one of its salt.
Alkaline buffer solution: Alkaline buffer solution is commonly made from a weak base and one of its salt and it having the pH value greater than 7.

Note: If you have a very weak acid and one its salt, this can produce a buffer solution which is actually alkaline. Buffers are important for reaction or processes which need specific \[pH\] ranges to happen.