NTA Abhyas JEE Main2020ChemistryIonic EquilibriumPractice
What is H + in a solution that is 0.01 M in H C N and 0.02 M in NaCN? br /> ( K a for H C N = 6.2 × 1 0 - 10 )
Options
- A3.1 × 1 0 10
- B6.2 × 1 0 5
- C6.2 × 1 0 - 10
- D3.1 × 1 0 - 10
Correct answer
D. 3.1 × 1 0 - 10
Step-by-step solution
K a   =   H +   CN − HCN 6.2 × 1 0 - 10 = [ H + ] [ 0.02 ] [ 0.01 ] NaCN = CN − due to common ion effect H + = 6.2 × 1 0 - 10 × 0.01 0.02 = 3.1 × 1 0 - 10