Question

What is the pH of Arterial blood?

(a) 7.25

(b) 7.30

(c) 7.35

(d) 7.40

The question was asked in my homework.

My question is from Spirometry topic in section Pulmonary Function Analysers of Biomedical Instrumentation

Answer 1

Correct answer is (d) 7.40

Easy explanation: Arterial blood has a pH of approximately 7.40. As venous blood acquires carbon dioxide, forms carbonic acid and hydrogen ions, the venous blood pH falls to approximately 7.36. This pH drop of 0.04 units occurs when the CO2 enters the tissue capillaries. When CO2 diffuses from the pulmonary capillaries into the alveoli, the blood pH rises 0.04 units to bring the normal arterial value of 7.40.