Problem solving tips

## Equilibrium

- Have a look at some problem solving tips to help you score more.
1
Salt Hydrolysis In order to understand what kind of hydrolysis a salt will undergo, follow these simple steps:
• Salts are composed of two parts, cations(+vely charged ions) and anions(-vely charged ions).
• In a salt, cation generally comes from the base and anion comes from the acid.
• Salts formed from strong acids and weak bases undergo cationic hydrolysis to give an acidic solution.
• Salts formed from weak acids and strong bases will hence undergo anionic hydrolysis to give a basic solution.
• Salts formed from strong acids and strong bases will not undergo hydrolysis.
• Salts formed from weak acids and weak bases will undergo Cationic -Anionic hydrolysis(As both Cations and Anions will undergo hydrolysis).
• The pH and can easily be calculated by the following table:
A weak acid has the dissociation constant , It forms a salt in reaction with alkali. The degree of hydrolysis of solution if is:
A
%
B
%
C
%
D
%
In the aqueous solution of sodium acetate the ion that undergoes hydrolysis is :
A
B
C
and
D
An aqueous solution of salt is alkaline. This shows that salt is made from:
A
a strong acid and a strong base
B
a strong acid and a weak base
C
a weak acid and a weak base
D
a weak acid and a strong base
2
Solubility Product and solubility of any salt You can find the solubility product of a salt of the type , where is its solubility, by using a simple formula:

Let's apply this to a salt of formula . of this salt with solubility as 's' will be:-
If the solubility of is mole/lit. Then its solubility product is:
A
B
C
D
The solubility product of NaCl is . Its solubility is:
A
B
C
D
of  solution is 12. Its solubility product is :
A
B
C
D
3
Finding Conjugate acid or Base Figuring out the conjugate acid or base can get tricky. But following a few simple steps can help you:
• In order to find the conjugate base of a given ion, you need to remove the atom from its formula and add a charge of-1 to the overall charge of the species.
For example, to find the conjugate base of , remove the H atom from the formula and add a charge of -1 to the total charge. This will result in .
• In order to find the conjugate acid of a given ion, you need to add a atom to the formula and add a charge of +1 to the overall charge of the species.
For example, to find the conjugate acid of , add a H atom to the formula and add +1 to the total charge. This will result in .
• Also, remember a strong acid/base will always give a weak conjugate acid/base and a weak acid/base will give a strong conjugate acid/base.
In the reaction, , the conjugate acid - base pair is:
A
B
C
D
The conjugate acid of is:
A
B
C
D
The Bronsted acid which gives the weakest conjugate base is:
A
B
C
D