What is the molarity?

Question

What is the molarity of lithium ion in an aqueous solution of 1.25 M lithium phosphate?

Answer 1

Hi Diana,

 

A lithium ion has a charge of +1, and a phosphate ion has a charge of -3. In order to have a neutral charge, the formula for lithium phosphate must be:

Li₃PO₄

 

Each mole of Li₃PO₄ contains 3 moles of lithium. Therefore, the molarity of lithium is 3 times that of lithium phosphate.

1.25 M Li₃PO₄ * 3 mol Li / 1 mol Li₃PO₄ = 3.75 M Li