Question

1L of N/2 HCl is heated in a beaker. It was detected that when the volume of solution was reduced to 600ml , 3.25g HCl is lost. Calculate final N of HCl

Answer 1

Normality = Gram equivalent /Volume of solution

HCl will lose or gain one electron so it's molar mass and gram equivalent mass will be same

Gram Equivalent = Given mass/Gram equivalent mass

Gram equivalent weight of HCl = 36.5 gm (mass of hydrogen + mass of chlorine)

Normality = N/2

It means in 1 litre solution 1/2 gram equivalent of HCl will be present

1/2 gram equivalent = 36.5/2 gm

So 18.25 gm of HCl will be present in 1L of solution

Now Volume reduced to 600 ml = 0.6 litre

3.25 gm of HCl lost so volume of HCl remain = 18.25-3.25 gm = 15 gm

Gram equivalent of HCl = 15/36.5 = 0.412

So Normality = Gram equivalent of HCl/ Volume of solution = 0.412 / 0.6 = 0.685 N

Final normality of HCl = 0.685 N

Answer : 0.685 N