Which of the following is NOT one of the body’s chemical buffering systems?
A) phosphate
B) bicarbonate
C) hydrochloride
D) hydrochloride, bicarbonate and phosphate are all buffering systems
Answer:
The correct answer is option C.
Why option A is incorrect:
Phosphate buffered is a solution which is commonly used in biological research. It is a water-based salt solution containing sodium chloride and sodium hydrogen phosphate. Therefore, this option is incorrect.
Why option B is incorrect:
Bicarbonates are also a buffer solution which maintains PH level in the bloodstream. Therefore, this option is wrong.
Why option D is incorrect:
Bicarbonates and phosphates are buffered solution; therefore, this option is also wrong.

Explanation:
Hydrochloride is not one of the body’s chemical buffering systems. Hydrochloric acid is a strong acid. It is not a weak acid, so the combination of these two solutes cannot make a buffer solution.
Chemical Buffer:
A buffer is a solution that resists dramatic changes in PH. Buffers are composed of a weak acid or a weak base; therefore, it maintains the blood PH level in a body.
For example:
A chemical buffer can be made of dissolved acetic acid, which is a weak acid and sodium acetate which is a salt derived from that acid.