Question

The function of buffer solution is:
(A) To increase the pH value in chemical reaction
(B) To decrease the pH value in chemical reaction
(C) To increase or decrease the pH value of according the need
(D) to keep the pH value constant in chemical reaction

Answer 1

Buffer solutions react with the protons or hydroxide ions present in the solution to produce salts. Addition of acid to a solution will increase the pH value and addition of a base will decrease the pH value.

Complete step by step solution:
Buffer solutions are the solutions that resist the change in pH of the solution when a small amount of acid or base is added into the solution.
- So, when acid is added to a solution, its pH will decrease because acid has protons, but if buffer solution is added to the solution mixture, then it will resist the changes in pH values of the solution.
- Same case is with bases, when they are added to the solution, the pH value will increase but if a buffer is present there, then it will not allow the pH to change.
So, we can say that correct answer is (D) to keep the pH value constant in chemical reaction

Additional Information:
- Many of our body fluids have these buffer systems because keeping pH at constant value is important.
- There are two types of buffer solution, acidic buffer and basic buffer. A mixture of acetic acid and sodium acetate acts as an acidic buffer around pH 4.75 and a mixture of ammonium chloride and ammonium hydroxide acts as a basic buffer around pH 9.25.

Note:
Here, do not mean that buffer solutions can change the pH of the solution according to our need but they actually resist the change in pH because they are actually solutions of salts. Remember that buffer solutions only work upto some limit, over addition of acid or base in the solution will not keep the pH constant.