Question

Calculate the pH of an aqueous solution of 16 mL of 0.00046 M HClO4(aq) after dilution to 42 mL.

Answer 1

1000$cm^{3}$ of HClO_{4} [/tex] contain 0.00046mol
16$cm^{3}$ of HClO_{4} [/tex] contain  x
                       x = $\frac{16cm ^{3} * 0.00046mol}{1000cm x^{3} }$
                       x = 0.00000736mol


$M_{1} V_{1} = M_{2} V_{2}$
(0.00000736mol)(16$cm^{3}$)= $(x) (42cm^{2})$
         $x= \frac{(0.00000736mol) * (16cm^{3}) }{42cm^{3} }$
                  =  0.000002803mol


pH= -log [$H^{+}$]
    = -log (0.000002803cm$^{3}$
    = 5.55