Question

What is the pH of 0.5 mol dm-3sodium hydroxide solution

Answer 1

The pH of a 0.5 mol dm-3 sodium hydroxide solution is 12.15.

Step-by-step explanation:

The pH of a sodium hydroxide (NaOH) solution can be determined by using the equation:

pH = 14 - pOH

First, we need to find the concentration of the solution using the given information:

If 3.5 g of NaOH is dissolved in 2.5 dm³ of water, the concentration can be calculated as follows:

Concentration = (mass of solute / molar mass of solute) / volume of solution

Concentration = (3.5 g / 40 g/mol) / 2.5 dm³

Concentration = 0.035 mol / 2.5 dm³ = 0.014 mol/dm³

Now, we can calculate the pOH:

pOH = -log[OH-] = -log(0.014) = 1.85

Finally, we can calculate the pH:

pH = 14 - 1.85 = 12.15