Question

Given the following conjugate acid-base pairs and their Ka values at 25°C, which of the following acid-base buffer systems might be found in the human body

1. HN O2/N O2- ; Ka = 4.00×10-4

2. C6H5O H/C6H5O - ; Ka = 1.30×10-10

3. H2PO41- / HPO42- ; Ka = 6.4x10-8

4. HCO3-/CO32- ; Ka = 4.7x10-11

5. CH2Br COOH/CH2Br COO- ; Ka = 2.00×10-3

6. HCN /CN - ; Ka = 6.20×10-10

7. H3PO4/H2PO42- ; Ka = 6.9x10-3

8. HCOO /COO - ; Ka = 1.77×10-4

9. H2CO3/HCO3- ; Ka = 4.3x10-7

provise the right answer with proper explanation.

Answer 1

The Conjugate acid -base pair no 9 i.e Carbonic acid and its Conjugate base.This Pair is found in human body because this buffer maintain the PH of blood which is around 7.4 Blood contains large amount of Carbonic acid{H​​​​​​2​​​​​C03} (forms because of dissolved carbondioxide in our body)and bicarbonate{HCO3-}as base.