Question

A mixture of potassium dihydrogen phosphate and dipotassium hydrogen phosphate is an example of
A. Serum
B. Buffer
C. Plasma
D. None of the above

Answer 1

Hint: Serum is the fluid and solutes of the blood without fibrinogens. Buffer is the solution used to keep the pH constant. Buffer is used in nature for the regulation of pH. Plasma is a straw-coloured fluid of the blood, it is blood without all the blood cells.

Complete step by step answer: Simple phosphate buffer is used in many biological experiments. Phosphate buffer is highly soluble in water. It has a high buffering capacity. Phosphate buffer inhibits enzymatic activity and precipitates the ethanol.

Method for preparation of buffer:
1. Take 800ml of distilled water in a container.
2. Add 20.214g of \[N{a_2}HP{O_4} - 7{H_2}O\] .
3. Add 3.394gof \[Na{H_2}P{O_4}{H_2}O\] .
4. Adjust solution to final desired pH using HCI or NaOH
5. Add distilled water until volume is 1L
Phosphate buffer is also called Phosphate buffer saline (PBS). PBS is used widely because it is isotonic and non-toxic to most of the cells. Uses of buffer include; Most of the biological reactions proceed under low pH concentration only. Body of an organism uses a buffer to maintain the pH. So, the correct answer to the given question is option B. Buffer is a mixture of potassium dihydrogen phosphate and di-potassium hydrogen phosphate.
Hence, the correct answer is option B.

Note: The serum is the fluid and solute of blood which does not play a role in clotting. It is defined as blood plasma without fibrinogens. Whereas, Plasma is the clear fluid of the blood, the straw-coloured liquid portion of blood that remains after removing red blood cells, white blood cells, platelets and other cellular components.