# Help on DAT ACHIEVER GC Questioin

#### MaxL221

##### Member
10+ Year Member
What would be the percentage yield if 11.85 g of Na2S2O3 were obtained from a reaction mixture containing 12.60 g of Na2SO3 and 5.00 g of S?
Na2SO3 + S --> Na2S2O3

A. 55%
B. 60%
C. 65%
D. 70%
E. 75%

can some please explain this question step by step?

#### CJ122638

##### Member
10+ Year Member
What is the answer? I think it should be E) 75%

So 12.6g of Na2SO3 is 0.1 mol
this reacts with 0.15625 mol of S (5/32)

this means that Na2SO3 is the limiting reagent.

So you expect to make 0.1 mol of Na2S2O3 which would be 15.8g

But you only made 11.85. 11.85/15.8 = 75%

Is that right?

OP
M

#### MaxL221

##### Member
10+ Year Member
CJ122638 said:
What is the answer? I think it should be E) 75%

So 12.6g of Na2SO3 is 0.1 mol
this reacts with 0.15625 mol of S (5/32)

this means that Na2SO3 is the limiting reagent.

So you expect to make 0.1 mol of Na2S2O3 which would be 15.8g

But you only made 11.85. 11.85/15.8 = 75%

Is that right?
yep! thanks....great explination!