[kash]

could you be able to give me an idea to plan an experiment to dtermine the perecentage by mass of an ion in a given compound

[Mitch]

Could you be more specific. There is no one size fits all answer to that question.

[slug]

Could do a titration, for example, if you know the molarity of the acid and need to find that of the alkali, to find the percentage of one of the elements in the alkali. Find the volume of acid it takes to neutralise the alkali, use n=mv/1000 find the moles of acid, then you can get the moles & molarity of alkali then find percentage of the chosen element!