Buffer solution among the following options is :           

1. HNO₂ and NaNO₂           

2. NaOH and NaCl

3. HNO₃ and NH₄NO₃         

4. HCl and KCl

What is [H⁺] in mol/L of a solution that is 0.20 M in CH₃COONa and 0.10 M in CH₃COOH?

(K_a for CH₃COOH = 1.8 x 10^-5)       

1. 3.5x10^-4           

2. 1.1x10^-5

3. 1.8x10^-5           

4. 9.0x10^-6

A physician wishes to prepare a buffer solution at pH=3.58 that efficiently resist changes in pH yet contains only small concetration of the buffering agents. Which one of the following weak acid together with its sodium salt would be best to use ?           [1997]

1. m-chlorobenzoic acid (pK_a = 3.98)

2. p-chlorocinnamic acid (pK_a = 4.41)

3. 2,5-dihydroxy benzoic acid (pK_a = 2.97)

4. Acetoacetic acid (pK_a = 3.58)

In a buffer solution containing equal concentration of B^- and H B, the K_b for B^- is 10^-10. The pH of buffer solution is 

1. 10

2. 7

3. 6

4. 4

The pH of blood is maintained by CO₂ by and H₂CO₃ in the body and chemical constituents of blood. This phenomenon is called:

1. colloidal                           

2. buffer action

3. acidic                               

4. salt balance