Question

Calculate the volume of water to be added to 400ml of seminormal hcl solution ti make decinormal

Answer 1

N1V1=N2V2 is the formula of dilution.
(1/2)× (400)= (1/10)× V2
V2= 2000ml
Now, since there's already 400 ml from beginning we need to add 1600 ml.

Answer 2

Let the initial concentration of HCL solution be N₁ and  volume of solution V₁ and  final concentration be  N₂ and  volume of solution V₂

Given,

N₁ = 1/2 (semi-normal)

N₂ = 1/10 (deci-normal)

V₁ = 400 ml

V₂ = ?

We know that,

$N_1V_1=N_2V_2\\\\\frac{1}{2}\times400=\frac{1}{10}V_2\\\\V_2=2000ml$

Final volume  of  solution = 2000 ml

Volume  of  added  water  = 2000 - 400

                                            = 1600 ml

                                           = 1.6 ltr