Question

What is the molarity if a sodium hydroxide solution if 0.555 g KHP is titrated with 23.71 mL NaOH?This NaOH solution is then used to titrate with an unknown acid. If 21.77 mL of NaOH is needed to titrate 0.310 g unknown, what is the molar mass of the unknown acid?

Please answer the second part of this.

Answer 1

Solution :

The reaction can be given as :

Molar mass of KHP = 204.22 g

We can also say that, 204.22 g KHP = 1 mole KHP

So, 0.555 g KHP = (1/204.22) 0.555 = 0.00272 mol KHP

From the reaction, we can see that ;

1 mole KHP reacts with = 1 mole NaOH

So, 0.00272 mole KHP will react with = 0.00272 mole NaOH

Molarity = (Number of moles of solute) / Volume of solution in liters = 0.00272 / 0.02371 = 0.1147 M

Or, Molarity = 0.115 M

Now, we have to calculate the moles of unknown ;

Therefore, molar mass of unknown acid = 124 g/mol