Answer:
11.05( to 2 decimal places).
Explanation:
Without mincing words let's dive straight into the solution the above problem. So, we are given the following parameters which are going to help us in solving this problem;
The mass of sodium hydroxide (NaOH) pellets given = 0.20g and the volume = 4.5 L of solution.
Therefore, the concentration of the solution = number of moles/ volume.
Note that The numbers of moles = mass/molar mass= 0.20g / 40 = 0.005 moles.
Hence, the concentration of the solution = number of moles/ volume = 0.005 moles / 4.5L = 0.00111 M.
pOH = - log[ OH^-] = - log [ 0.00111] = 2.955.
Note that; pH + pOH = 14.
Therefore, pH = 14 - pOH.
pH = 14 - 2.955 = 11.045 = 11.05( to 2 decimal places).
