Question

2. Carbonic acid in the blood forms one of the most important buffer systems in our body. When our tissues are burning metabolic fuel they produce H+ and CO2. The enzyme carbonic anhydrase use H2O to convert most of the CO2 into carbonic acid (H2CO3).

H2O (l) + CO2(g)                     H2CO3(aq)

If a person holds their breath and swims 25 m underwater i) What will happen to the pH of their blood at the end of this swim? ii) explain the chemical reasoning behind this this change.

Answer 1

f a person holds their breath, then percentage of CO2 in the body increases.

then CO2 (g) react with H2O to form H2CO3.

H2CO3 .................> H+ + HCO3-

we know,

pH = - log [H+]

thus

here concentration of H+ increases in the blood and hence pH decreases.

pH of their blood at the end of this swim decreases.

H2CO3 is weak and it is partially ionizes to produce H+ ion which is responsible decreasing the pH of blood.