[benn121]

Hi guys, I feel cheeky asking for help but im doing a civil engineering phd and i have to do an element of chemistry in it. The problem is i have to answer a few questions to put in my thesis as regards to checmistry. I have done all of them except this one,

Calcaulate the molar concentration of hydroxyl ions (OH-) when 260 mg of potassium hydroxide (KOH) are dissolved in 0.5 litres of pure water and hence find the pH of this alkaline.

I have researched how to find the molar concentration and I have come up with an equation CX = NX / Vsoh

Is this right? can anyone offer any help or advice?

Thank you if you can

[Albert]

First, you have to convert mg into moles by dividing the weight by the molecular weight of potassium hydroxide.

Then, you calculate the molarity of hydroxyl ions: moles/Volume. Once here, you calculate the pOH (-log molarity of OH^-).

pH = 14- pOH

[benn121]

That is brilliant thank you very much for your help