silver nitrate+sodium chloride-bromide條equation係什麼？

Question

救救我吧,明天要交功課

但係solution係mixed sodium chloride-bromide,然後用silver nitrate做titration去找sodium chloride-bromide的concentration,請幫幫忙

but i know the concentration of AgNO3,is it =i know the concentration of Ag+？

also,if i can find the concentration of Br- and Cl-,is it = i can find the concentration of the sodium chloride-bromide solution？

Answer 1

AgNO3(aq) + NaCl(aq) ----> AgCl(s) (white precipitate) + NaNO3(aq)
AgNO3(aq) + NaBr(aq) ----> AgBr(s) (yellow precipitate) + NaNO3(aq)
This is called silver nitrate test. The test can distinguish what kind of halogen ion is present in the solution by looking at the colour of precipitate. It is better to add dilute nitrate acid to dissolve other non-chloride precipitate when you want to test for chloride ions.

2006-10-31 19:55:59 補充：
As you know the concentration of AgNO3, then by using the formula no. of moles=molarity x vol (burette reading), you can calculate the total no. of moles of sodium chloride-bromide by adding the no. of moles of NaCl and NaBr together. But do you have any other information?

2006-10-31 19:56:11 補充：
Like ratio of sodium chloride: sodium bromide. Otherwise it is impossible to find the concentraion of sodium chloride-bromide.For your second and third question, they are true. Because they are in 1:1 ratio. Say AgNO3's concentraion is 1M, then concentraions for Ag+ and NO3- are both 1M.

Answer 2

You already see the equations above.

As you are doing titration to find the concentration, the concentration of Ag should already known. From the burette reading, you can calculate the no. of mole of Ag+
you can work out [Cl-] + [Br-], unless there is other information, the value of [Cl-] and [Br-] can not be worked out.

Answer 3

AgNO3(aq) + NaCl(aq) ----> AgCl(s) (white precipitate) + NaNO3(aq)
AgNO3(aq) + NaBr(aq) ----> AgBr(s) (yellow precipitate) + NaNO3(aq)