Question

When 0.03 moles of lead(II) nitrate are dissolved in enough water to make 266 milliliters of solution, what is the molar concentration of nitrate ions?
Answer in units of M

I already tried moles per liter and it says it is wrong.

Answer 1

Now that you know what you did wrong on the other two you know what yu did wrong on this one and you should be able to correct it yourself. You aren't reading the problem(s) correctly.