Calculate the pH of each of the following strong acid solutions: (b) 1.52 g of HNO3 in 575 mL of solution

Video transcript

Hello everyone. So in this video we're solving for the ph of a solution giving the mass and the volume of that solution. Alright, so first we know that H B. R is a known strong acid. What that means is that HbR will completely dissociate into its ions. More importantly, what we're concentrating on is going to be our H plus ions. So first let's go ahead and write the chemical equation for this. So H B R, which is a quiz, is going to go ahead and associate into H plus carry ons which is of course Aquarius and R. B. R minus and ions. And of course that is also Aquarius. So for starting off my dimensional analysis, what we're given in this problem is the mass of my H B. R. Which is a value 2.25 g of H B. R. And we're also given the volume of the solvent which is water. In our case that's a value 575 mL. I'll just write writer as H 20. So first things first, we want to go ahead and go ahead and change the male leaders into leaders. So to cancel that we'll put metal layers on top and leaders on the bottom. So for every one liter of solution we have ml, I can see now that the male liters of water will go ahead and cancel out. Next step is to go ahead and use smaller mass of HBr. So we'll put one mole of H. B. R on top and the mass of Hbr on the denominator to cancel that out. So that's a value 80.91194 g of H P. R. We see now that the grams HBR will cancel. Lastly we go ahead and use geometry to go ahead and solve for the moles of H plus. So we see her, we have a 1 to 1 ratio. So in the denominator will have one mole of H. B. R. And the numerator, numerator will have one mole of our H plus cad ions. Again you can see that the moles of H. P. R. Will cancel. So putting all this into my calculator, the concentration of my H plus is going to be 0. moller. And remember that the concentrations of other unit of concentration is going to be most over leaders and that's exactly what we have. So now that we have the concentration of R. H. Plus, we can go ahead and solve for the ph of a solution. If you recall the equation for P H. Is of negative log time, see concentration of H plus which is what we saw for. So let's go ahead and actually plug that in. So negative log time or negative log of 0.0483618. So once I put that into my calculator, I see that my ph value is going to be 1.315. So this is going to be my final answer for this question. Thank you all so much for watching.