NTA Abhyas JEE Main2020ChemistryIonic EquilibriumPractice
The pH of blood stream is maintained by a proper balance of H 2 CO 3 and N a H C O 3 concentration. What volume of 5M N a H C O 3 solution should be mixed with 10 ml sample of blood which is 2 M in H 2 C O 3 in order to maintain a pH of 7.4 ( K a for H 2 C O 3 in blood is 4.0 × 1 0 - 7 ) ?
Options
- A40 ml
- B35 ml
- C25 ml
- D38 ml
Correct answer
A. 40 ml
Step-by-step solution
H 2 C O 3 in blood = 2 M Volume of blood = 10 ml N a H C O 3 = 5 M Let volume of N a H C O 3 used = V ml H 2 C O 3 in mixture = 2 × 10 v + 10 N a H C O 3 in mixture = 5 × v v + 10 pH = pKa + log salt acid 7 .4 = -log (4×10 − 7 ) + log 5 × v v + 10 2 × 10 v + 10 v = 40 ml