 So we learned that if you have a solution A, the concentration does not change if you have one liter of that solution or two liters of that solution. But what happens if you add more solvent? Remember solute is the thing that gets dissolved by the solvent and solvent is the majority of the solution. So the relationship between the volume and the concentration is on indirectly proportional relationship. That means if you increase the volume without adjusting the amount of solute, accordingly the concentration will decrease. So say you have a cup of salt water. If you add more water into the cup without adding more salt, you will say that the salt water is now diluted. And that means the concentration of the salt in the salt water solution has been reduced. So the relationship is initial volume times initial concentration equal final volume times final concentration. So let's do a question so we can have a better understanding of what that means. So you have 200 ml of a 3.0 molar sodium chloride solution. If you diluted to one liter, what would be the new concentration of the sodium chloride solution? So let's summarize the question. Vi the initial volume is equal to 200 ml, equal to 0.2 liters. So let's convert to liters so you can see that we are dealing with liters everywhere in the question. You have 3 molar means 3 mol per liter and you have 1 liter over here in the question as well. Ci equal to 3 molar. Okay next if you diluted to one liter so that means Vf the final volume is equal to one liter. What will be the new concentration? So our challenge is to find the final concentration Cf. Let's apply their relationship approach. One simple way to think about this is whatever you want to find let it be Cf or Vi. Keep it there in this side of the equation and move the term next to the other side and flip it. So what do you mean by that? So you have Vi Ci equal Vf Cf. So if you want to find Cf then the term next to Cf is Vf. What you need to do is move that Vf onto the other side and flip it so you divide. What if you want to find Vi for example while already knowing Ci, Cf and Vf? Well you simply just keep Vi there and bring Ci to the other side and divide that term by Ci. Okay let's get back to the question. The final concentration of the Sodium chloride solution is therefore Cf equal to Vi Ci divided by Vf and that will be equal to 0.60 moles per liter. So after adding more solvent to the solution the concentration is diluted down to 0.6 moles per liter instead of 3 moles per liter. Now if you take 200 millilitres out of this 1 liter of diluted solution put in a new beaker then make it up to 1 liter again will be the new concentration. So I would like you to calculate this but the answer is that the final concentration will be 0.12 moles per liter. Now notice the volume ratio so you take 200 mil of a solution and diluted to 1 liter. Now the dilution factor of that dilution is 0.2 to 1 or 1 to 5. It means that every time you take out 200 millilitres and diluted to 1 liter we are decreasing the concentration by 5 times.