How many moles of Na2S2O3 are needed to react with 5 mg of AgBr to form NaBr + Na3[Ag(S2O3)2]?

Question

Na2S2O3 is sodium thiosulfate.
AgBr is silver bromide.
NaBr is sodium bromide.

Answer 1

balanced equation...2Na2s203+AgBr =NaBr+Na3[Ag(S2O3)2]
mass of AgBr.. 5*10^-3g (0.005)
molar mass of AgBr is 187.9
no of moles of AgBr used= 0.005/187.9
=0.0000266
from d equation ratio of NA2S2O3 to AgBr is 2:1.
therefore the no of moles of NA2S2O3 is 2*0.0000266 =0.000053

Answer 2

Balance the eqn 1st..

2 Na2S2O3 + AgBr --> NaBr + Na3[Ag(S2O3)2]

1.find no of mole of AgBr
2. No of mole of Na2S2O3 = 2 x no of mole of AgBr

Hope it helps you.