An aqueous solution contains 1.2 mM of total ions. (b) If the solution is FeCl3(aq), what is the concentration of chloride ion?

Video transcript

Hey everyone, we're asked to calculate the polarity of potassium ions in a solution of potassium chrome eight with a total ion concentration of 0.45 molar 1st. Let's go ahead and write out our reaction. So we have potassium chrome eight and this is going to disassociate into our potassium ions plus our chrome eight ions. To balance this out, we can go ahead and add a coefficient of two prior to our potassium ion. To answer this question, it will be easy for us to use one variable since we know that X plus Y equals 0.45 molar. So if we let X equal Our concentration of our chrome eight ion and why equal our concentration of our potassium ions, This means that our potassium ions is equal to two times our chromium ions. In other words why is going to equal to X. So plugging that into our equation, we have X plus two X equals 0. molar. We get three x equals 0.45 molar. And when we divide both sides by three We get x equals 0.15 molar. And since our X stood for our concentration of our chrome ei on that means we have to find two times X. To get our concentration of potassium ions. So this is going to come up to two Times 0. Molar. And our final answer is going to be 0.30 moller. So I hope that made sense. And let us know if you have any questions