what is the molarity of Br^- in each solution? a. 0.100 M KBr

Video transcript

All right. Hi, everyone. So this question is asking us what is the molarity of bromide in each solution? And here we have 0.175 molar sodium bromite. Now here on the screen, we have four different answer choices labeled A through D proposing different molarity or bromide in the given solution. So recall first and foremost that the capital m here stands for molarity and molarity is equal to the moles of a given salute per every liter of solution. Now, in the given value, right, the solute is sodium bromide. So using the ratios of sodium bromide to bromide, we can convert the molarity of sodium bromide into that of just bromide. So taking our molarity, we have 0.175 moles of sodium bromide per every liter of solution. So using the mole ratios provided we can see that one mole of sodium bromide dissociates into one mole of bromide ion. Notice how in my conversion factor using our mole ratios, moles of sodium bromide are in the denominator. And the reason for this is to ensure that those units cancel out leaving my answer only in reference to the moles of bromide. So 0.175 multiplied by one and then divided by one equals 0.175 moles of bromide per every liter of solution. And so the molarity of bromide is equal to that of sodium bromide, which is 0.175 molar and there you have it. So our answer corresponds to option C in the multiple choice. And with that being said, thank you so very much for watching. And I hope you found this helpful.