If 448.85 mg of koh is dissolved in 400 ml of water, what will be the ph of the solution?

I have provided the steps and solution within the attachment. The pH of the solution would be 12.30, this indicates that the solution is basic, as a higher value of pH indicates presence of more hydroxide ions and less of hydrogen ions in the solution.

Although the diagram is not shown, i know that the convection is heated by a the core.