Question

How many milliliters of 0.0160 M Na2S2O3 solution are needed to dissolve 0.510 g of AgBr?
AgBr(s)+2Na2S2O3(aq)→Na3Ag(S2O3)2(aq)+NaBr(aq)

Answer 1

AgBr(s) + 2Na2S2O3(aq) ------------> Na3Ag(S2O3)2(aq) + NaBr(aq)

From the above, balanced equation,

2 moles of Na2S2O3 is required to dissolve 1 mole of AgBr.

No.of moles of AgBr = mass / molar mass = 0.510 / 187.7 = 0.00272 mol

So. no.of moles of Na2S2O3 required = 0.00544 mol

=> Volume = n / conc. = 0.00544 / 0.0160 = 0.34 L

Volume ( in mL ) = 340 mL <<<<<<------------(ANSWER)

Therefore 340 mL of Na2S2O3 is needed to dissolve 0.510 g of AgBr.