Question

Calculate the molarity of each aqueous solution: (a) 25.5 ml of 6.25 m hcl diluted to 0.500 l with water (b) 8.25 ml of 2.00×10–2 m ki diluted to 12.0 ml with water

Answer 1

1. Using the dilution equation;
M1V1=M2V2
M1 = 6.25 m, v1= 25.5 ml or 0.0255 liters
Therefore; (6.25 ×0.0255)= M (0.5)
                 M = 0.159375/0.5
 Therefore Molarity is 0.31875 M Hcl

2. From the same equation 
 M1v1=m2v2
m1 = 0.02 m, v1=8.25 ml or 0.00825 l, while v2= 0.012 l
Thus, 0.02 ×0.00825 = M (0.012)
          M = 0.000165/0.012
              = 0.01375 m
Thus molarity is 0.01375 M KI