We know that Normality of HCL is 12N
According to the formula
N1 = 12N
N2 = 1N (Given)
V2 = 100 ml
Substituting the values in the above formula we get
12 X V1 = 1 X 100
If we add 8.33mL in 100 L of water we get 1 N HCl.