Assume that you have an aqueous solution of an unknown salt. Treatment of the solution with dilute BaCl2, AgNO3, and Cu(NO3)2 produces no precipitate. Which of the following anions might the solution contain? (a) Cl- (b) NO3 (c) OH- (d) SO4- 2-

Video transcript

Hello everyone today we are being given the falling problem, consider a solution with an unknown salt. When dilute solutions of calcium nitrate, lead nitrate and gold nitrate are added to the solution. They all form a precipitate, identify the an eye on that the solution contains. So the fact that it forms that precipitate lets us know that it is considered insoluble. And so right off the bat we can get rid of answer choices A. Because all chlor 8s are soluble. So that leaves B. C. And D. Let's start from D. And work your way up. Ask this question stated. We are going to react our phosphate P. 043 minus. We're going to react that with our calcium nitrate first and these are both Aquarius and they are going to form calcium phosphate which is actually going to be a solid and no treat ions. So this is actually going to be insoluble because phosphates are insoluble when paired with calcium. And so we have our first insoluble that we need and so we need the other two to be insoluble as well. Next we're going to react our phosphate with our lead nitrate. These are both going to be a quiz of course when they react we're going to get lead fast feet but it's gonna form in the solid form and we're also gonna get nitrate ions to and so we also have an insoluble precipitate here because phosphates insoluble when paired with lead as well. And lastly we're going to combine our boss feet with our it's gold nitrate. So as before we're going to have our phosphorus phosphate in the aqueous form reacting with our gold nitrate to form gold phosphate in the silver form and nitrate and the acquis. This is also going to be insoluble because phosphate is known to be insoluble when also paired with silver. And so since all three of these are insoluble, our answer is going to be D. And with that, we've answered the question overall, I hope that this helped, and until next time.