Question

Molarity of 0.2 N nacl​

Answer 1

Molarity = (number of moles of solute / volume of solution in liters)

Here number of moles = ( given mass of solute / molar mass )

whereas Normality = ( Number of gram equivalent / volume of solution in liter )

where gram equivalent = ( mass of solute / equivalent mass )

Consider an example of H2SO4 whose molar mass = 98 g per mole

Consider a Solution containing 0.98 g of sulphuric acid in 100 mL.

Volume = 100 ml = 0.1 L

Then,

Number of moles = 0.98 / 98

Number of moles = 0.01

Hence molarity = 0.01 / 0.1 = 0.1 M

Hence Molarity = 0.1 M

Now sulphuric acid is dibasic therefore

its equivalent weight = 98 / 2

Hence equivalent weight = 49

so the gram equivalent = 0.98 / 49 = 0.02

Now Normality = 0.02 / 0.1

Hence the Normality is equal to 0.2 N.

Thus For H2SO4 ( i.e. dibasic ) Normality is 0.2 N and molarity is 0.1M.