Buffers And Neutralisation

Question 1

What is the definition of a buffer solution?

Answer 1

A mixture that minimises pH change when small amounts of acids or bases are added

Question 2

What are the two components of a buffer solution?

Answer 2

1. Weak acid HA
2. Conjugate base A-

Question 3

How do you prepare a buffer solution from a weak acid and its salt?

Answer 3

Add the weak acid and a salt of the weak acid
The salt (MA) will dissociate to M+ and A- and will form the conjugate base form of the weak acid

Question 4

How to make a buffer from neutralisation?

Answer 4

Add a controlled amount of alkali to an excess of weak acid, this will partially neutralise the weak acid forming the conjugate base

Question 5

What is the relation between [H+] and [A-] in buffers?

Answer 5

[H+] DOES NOT EQUAL [A-]
Buffers are not the same as acids!

Question 6

How to calculate [H+] of a buffer?

Answer 6

[H+] = (ka x [HA]) / [A-]

Question 7

How to calculate Ka from pKa?

Answer 7

Ka = 10 ^-pka

Question 8

What is moles of OH- always equal to in a buffer?

Answer 8

Moles of OH - is always equal to moles of A-