The ph of blood depends on the [hco3-/h2co3] balance. ([h2co3] is equal to the amount of dissolved co2). calculate the bicarbonate (hco3-) : carbon dioxide ratio for a normal blood ph of 7.40. (the pka1 of carbonic acid is 6.10 at 37oc, body temperature). (a) 20 : 1 (b) 1.3 : 1 (c) 2 : 1 (d) 1 : 20 (e) 1 : 0.01

Option (A) is the correct answer.

Explanation:

The given data is as follows.

  pH = 7.40,         =

= 6.10

We have to find = ?

According to Henderson-Hasselbalch equation,

                 pH =

Hence, putting the given values into the above equation as follows.

                 pH =

or,              pH =

                 7.40 = 6.10 +

              = 1.30

          = antilog (1.30)    

                                         = 20

Since, it is given that = .

Therefore, or =

Thus, we can conclude that the bicarbonate (HCO3-) : carbon dioxide ratio for a normal blood pH of 7.40 is 20:1.

in the given question, the partial pressure is calculated by using the ideal gas equation, that is, pv = nrt

here, p is pressure, v is volume = 25 l, n is number of moles = 0.0104 moles, r is gas constant = -0.0821 l.atm / mol.k

t is temperature = 273 k

p = nrt / v

p = (0.0104 mol × 0.0821 l.atm / mol.k × 273 k) / 25 l

= 0.0093 atm