According to wikipedia, lemsip contains 650 mg of paracetamol and 10 mg phenylephrine hydrochloride. Based on this, I'd like to caclulate the pH of a 500 cm^3 standard solution of one of these capsules.
I know I'll have to use the Henderson–Hasselbalch equation, but I was curious as to how you can calculate the pH of a solution containing more than one chemical component?
Also... How would I find out the [A-]/[HA] ratio?
Sorry, potentially obvious answer here, I'm just stumped for some reason.
+++If you'd like to help even more, I'm going to acidify this solution & was wondering how I would find exact quantities of HCl I'd need to add to achieve a desired pH?