How many milliliters of 0.105 M HCl are needed to titrate each of the following solutions to the equivalence point: (b) 22.5 mL of 0.118 M NH3?

Video transcript

Hello everyone. So in this video we're gonna go ahead and calculate for the volume in milliliters of hydrochloric acid required to titrate our metal mean to the equivalence point. First thing I'm gonna do is write out my chemical equation. That's very useful in case we need to do any store geometry. It's also good just to kind of see what's going on in this reaction. So, first things first, like I said chemical equation. So of course we have our hydroponic asset as hbr reacting with our methyl amine which is C. H three and H two. That's going to go ahead and create one single product which is CH three And H three B. R. is also going to be in it's a great state. So, we also want to go ahead and recognize our units. We have the concentration of our capital M here that equals two moles over liters. All right, we're gonna get started with our dimensional analysis. What I'm gonna first use is going to be mega volume and my layers of my methyl amine which is given to us as 34.5 mL of R. C. H. Three and H. Two. I want to convert first our mail letters into leaders. So it's going to be 1000 mL per one liter of this. Um Next thing I wanna do is go ahead and use my concentration of methamphetamine again. This is given to us in the problem. So, we have to also recognize that the concentration unit is moles per leaders. So that is a conversion unit in itself. So, well, I will have on the bottom will be one leaders and then right on top I will have my moles which is 0.135 moles of my mental. I mean, okay let's go ahead and pause real quick. So we can go ahead and see if our units will cancel. We have milliliters canceling and leaders. So now we're left with our mole. What I want to go ahead and do now is because we're calculating for the volume. I want to really slowly start to get into my HbR units instead of melamine. What I'm gonna do is use my chemical equation and do a multiple ratio. You'll see everything here. All the regions is going to be a 1-1 mole ratio. So let's put one moles of HBR on top And then one mole of methamphetamine to go ahead and cancel out the unit. And now we have the units being in terms of our hydroponic acid. So next step here is to go ahead and use my concentration of hydrochloric acid. Again given to us in the problem. So we have 0.1 2 moles of hydrochloric acid over one leader again, you can see that the moles will go ahead and cancel left with our leader units. I'm gonna go ahead if I convert this into male leaders because the problem says we want the volume in milliliters is a very easy direct conversion, one liter of hbr and bottom And then 1000 millions of HBR on top. Again, you can see why I put this on the bottom so that the top and bottom can cancel. So I'm gonna go ahead and put all these numerical values into my calculator. Once I do so, I will get the value of 37. ml of hydrochloric acid. And this right here is going to be my final answer for this problem. Thank you all so much for watching.