Name: pH of a Solution
Uploaded: 2019-07-19
Duration: 4 min 31 s
Description: This video discusses the pH scale and how it is useful to determine the behaviour of an acidic or basic solution. Does it also tell what the pH of a neutral...

Question

What is buffer solution? Write the types of buffer solution with example. What are the applications of buffer solutions?

Accepted Answer

A buffer is a solution that can resist $pH$ change upon the addition of an acidic or basic solution. It is able to neutralise the small amounts of added acid or base, thus maintaining the $pH$ of the solution relatively stable. Buffer solutions have a working $pH$ range, and capacity which dictate how much acid/base can be neutralised before $pH$ changes, and the amount by which it will change. To effectively maintain a $pH$ range, a buffer must consist of a weak conjugate acid-base pair, [meaning either (i) a weak acid and its conjugate base, or (ii) a weak base and its conjugate acid].

Example: (i) ${CH}_{3} COOH + {CH}_{3} COONa$

Types of buffer solutions:

(a) Simple buffer: These can be prepared by mixing salt of weak acid and weak base with water. Example: ${CH}_{3} {COONH}_{4}, {NH}_{4} CN$ , etc.

(b Mixed buffer: There are two types:

(i) When a weak acid is mixed with its salt of a strong base, the buffer solution is formed. This is called an acidic buffer.

Example: The equimolar mixture of formic acid ( $HCOOH$ ) and sodium formate ( $HCOONa$ ) forms an acidic buffer.

(ii) When a weak base is mixed with its salt of a strong acid, it forms a basic buffer solution.

Example: The equimolar solution of ammonium hydroxide ( ${NH}_{4} OH$ ) with ammonium chloride ( ${NH}_{4} Cl$ ) forms a basic buffer solution.

Applications of buffer solutions:

(i) These are used in qualitative analysis of mixture. Quantitative analysis or estimations.

(ii) In the manufacture of paper, dyes, inks, paints, drugs, etc.

(iii) Digestion of food, preservation of food and fruits and preservation of agriculture and dairy products.

What is buffer solution? Write the types of buffer solution with example. What are the applications of buffer solutions?

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