Question

Select every combination of chemicals that will produce a buffer when dissolved in water.

		1.0 moles of sodium acetate
		1.0 moles of sodium acetate + 1.0 moles of potassium acetate
		1.0 moles of sodium acetate + 1.0 moles of acetic acid
		1.0 moles of sodium acetate + 1.0 moles of sodium hydroxide
		1.0 moles of sodium acetate + 0.5 moles of sodium hydroxide
		1.0 moles of sodium acetate + 1.0 moles of hydrochloric acid
		1.0 moles of sodium acetate + 0.5 moles of hydrochloric acid

Answer 1

Acidic buffer is formed by weak acid and salt of weak acid

Basic buffer is formed by weak base and salt of weak base

option 1:

Only conjugate base is present

This will not form buffer.

option 2:

Both the components are conjugate base of acetic acid

This will not form buffer.

option 3:

CH3COOH is weak acid.

CH3COONa is its conjugate base.

This will form buffer.

option 4:

CH3COONa is conjugate base and NaOH is base.

This will not form buffer.

option 5:

CH3COONa is conjugate base and NaOH is base.

This will not form buffer.

option 6:

CH3COONa is conjugate base and HCl is strong acid.

1.0 moles of each will react to form 1.0 mol of CH3COOH which alone cant form buffer

This will not form buffer.

option 7:

CH3COONa is conjugate base and HCl is strong acid.

0.5 moles of each will react to form 0.5 mol of CH3COOH

Also there are 0.5 mol of CH3COONa remaining.

This will form buffer.

Answer: option 3 and 7