Question

128. Calculate pH of a solution
100ml contains
0.2 g NaOH dissolved in it
(1) 10.699
(3) 12.699
(4) 13.699​

Answer 1

Answer:

The molarity of this solution is to be calculated first. 1M NaoH = 40 g NaOH per one liter of solution. 100 mL = 0.1 L of NaOH solution and 0.2 g NaoH is 0.2 g/40 g/mole. It is 0.005 moles NaOH per 0.1L or 0.05 mole per Liter

Solving for its concentration results to 0.05 M.

pOH = -log[concentration of -OH] will give you pOH = 1.3

pH = 14–1.3

The pH of the said solution of NaOH is 12.7.