Question

1g of dibasic acid is compeletely neutrialised with 100 ml of 0.5 N NaOH solution. what is molar mass of acid

Answer 1

Given:

1g of dibasic acid is completely neutralised with 100 ml of 0.5 N NaOH solution.  

To find:

What is the molar mass of acid?

Solution:

From given, we have,

100 ml of 0.5 N NaOH  

⇒ Normality of NaOH = 0.5 N and Volume of NaOH = 100 ml

Normality is calculated as follows:

Normality = Moles / Volume  

⇒ Moles = Normality × Volume

⇒ Moles = 0.5 × 100/1000       (∵ 100 ml = 100/1000 litre)

∴ Moles = 0.05

As an acid is dibasic, therefore, 1 mole of this acid will neutralise 2 moles of NaOH.

∴ Moles of acid required to neutralise 0.05 moles of NaOH  

= 1/2 × 0.05

= 0.025 moles

∴ Molar Mass of Acid = Given Mass/Moles

∴ Molar mass = 1/0.025 = 40

Therefore, the molar mass of acid is 40.