Question

a) Calculate the volume of 0.010M NaOH required to make a 200.0 mL solution of NaOH with pH=11.00

b) Calculate the volume of 0.100M HCl required to make a 200.0 mL solution of HCl with pH=2.00

Answer 1

a)

pH = 11.00

pOH = 3.00

[OH-] = 1.00 x 10^-3 M

concentration C1 = 0.010 M

C2 = 0.001 M

volume V1 = ??

V2 = 200 mL

C1 V1 = C2 V2

0.010 x V1 = 0.0010 x 200

V1 = 20 mL

volume of NaOH needed = 20.0 mL

2)

pH = 2.00

[H+] = 1.00 x 10^-2

C1 = 0.10 M

C2 = 0.010 M

V2 = 200 mL

C1 V1 = C2 V2

0.10 x V1 = 0.010 x 200

V1 = 20 mL

volume of HCl needed = 20 mL