 Let's try this one now. So a titration was performed on 25 mils of an unknown hydrochloric acid samples using 0.09134 molar sodium hydroxide as the titration. It required 35.05 mils of sodium hydroxide to reach the color change endpoint. What's the molarity of the HCl solution? So the first thing you have to realize is that you're reacting HCl with NaOH. This is a neutralization reaction, so you're going to make H2O plus NaCl, the double displacement acid-base neutralization reaction. Balanced already. So now let's write down the information that it gives us. So it says the volume of the HCl is 25.00. It also says that, or we'll say solutions. It also says that the molarity of the NaOH solution is 0.09134 molar sodium hydroxide. And it gives us the volume of sodium hydroxide used on volume of NaOH, 35.05 mils. Okay, what's the molarity of HCl? So don't do an M1B1 thing on this, okay? So this we have to use the reaction equation to do moles to moles and all of that stuff. So some of the things that we can change really quick. Let's just change this to moles of NaOH per one liter of solution. Okay, let's change this. Let's figure out how many liters of solution we have. Do this, I'm just going to do it and you guys can watch it later, okay? Okay, so that's going to kill that, right? So we've got that many moles, so that will give us the number of moles of NaOH we've got. Okay, so let's figure out the number of moles of NaOH. It's 6.78 times that to negative 4. So moles to moles of NaOH to NaCl, right? So it's a one to orange, one mole NaOH, one mole HCl. So that'll give us the number of moles of HCl, the same number of moles. Do we know how many liters of solution we've got? So take this, divide it by 0.0.02500 liters of solution. 1, 4, 0, 1, 2, 8, 1, molar HCl solution. Any questions? No. Quick. If there's any questions, quick. Okay.