Ionic Equilibria

Question 1

What are strong electrolytes and examples

Answer 1

Substances which when dissolved in a solvent are completely ionised

NaCl, HCl

Question 2

What are weak electrolytes

Answer 2

Substances which when dissolved in a solvent are not completely ionised. Solution has ions and molecules

Question 3

What are non electrolytes

Answer 3

Substances which when dissolved in a solvent do not ionise or dissociate

Glucose in water

Question 4

Counter ions

Answer 4

Due to electrostatic interactions, ions of opposite charge will cluster together so in the vicinity of any particular ion there will be a a lot of ions of opposite charges

Question 5

Ionic atmosphere

Answer 5

Environment of a particular ion therefore carries an opposite charge and this diffuses into a charged atmosphere

Question 6

What is ionic strength

Answer 6

A measure of the total ion concentration

Question 7

The activity of an ion depends on what

Answer 7

Concentration by the activity coefficient (y)

For very dilute ionic solutions, y approaches 1 and activity equals concentration. As ionic strength increases, y typically decreases

Question 8

Ionic product of water , Kw

Answer 8

Kw= [H3O+] [OH-]

1.-08x 10^-14

Question 9

Relationship between pKa and pKb

Answer 9

KaKb=Kw

Question 10

Strong acid + strong base

Answer 10

Neutral salt

Question 11

Strong acid and weak base

Answer 11

Acidic salt

Question 12

Weak acid + strong base

Answer 12

Basic salt

Question 13

Weak acid + weak base

Answer 13

Neutral salt

Question 14

Salts of weak acid

Answer 14

Alkaline due to salt hydrolysis

Question 15

What is a buffer solution

Answer 15

Resists changes to pH when an acid or base is added

Weak acid and its salt

Question 16

Buffer capacity

Answer 16

The amount in moles of acid or alkali that much be added to one litre of the buffer to produce a unit change in ph

Question 17

Formula for is-electric point pHiso

Answer 17

PKa1 +pKa2 / 2

Question 18

Activity formula

Answer 18

Y x C

Activity coefficient x concentration

Question 19

2 approximations of Henderson hasselbach

Answer 19

Conc of A- is equal to initial amount of salt added to solution because the salt completely dissociates in solution

Conc of HA is equal to until a amount of acid added because very little of the acid dissociates