Question

Part A.)

0.30 M HBr

Express your answer using two decimal places.

pH=

Part B.)

3.5×10⁻⁴ M KOH

Express your answer using two decimal places.

pH=

Part C.)

4.7×10⁻⁵ M Ca(OH)2

Express your answer using two decimal places.

pH=

Answer 1

Part A.

0.30 M HBr

for strong acids,

pH = -log (conc. H+)

    = -log ( 0.3)

   pH = 0.52   ........... Answer

PART B

3.5×10⁻⁴ M KOH

[OH-]= 3.5 x 10^-4 M
pOH = - log (3.5 x 10^-4) = 3.46

pH = 14- pH

    = 14-3.46

   pH = 10.54   ................. Answer

PART C

4.7×10⁻⁵ M Ca(OH)2

[OH-]= 2 x 4.7 x 10^-5 = 9.4 x 10^-5 M ........... as Ca(OH)2 has 2 OH- ions
pOH = - log (9.4 x 10^-5) = 4.02

pH = 14 - 4.02

   pH = 9.98 ............. Answer