Question

When 125 mL of 0.500 M AgNO3 is added to 100. mL of 0.300 M NH4Cl, how many extra mLs of excess reactant were used? AgNO3 (aq) + NH4Cl(aq) → AgCl(s) + NH4NO3 (aq)

Answer 1

We have to first find the limiting reagent among the two. Let us calculate the total number of moles of each-

Since the moles of NH4Cl are less in number (30 mmol), that is the limiting reagent.

According to the balanced equation,

one mole of AgNO3 reacts with one mole of NH4Cl. Therefore, 30 mmol of AgNO3 will react with 30 mmol of NH4Cl. So, the excess reactant is AgNO3.

Excess moles of AgNO3 = (62.5 - 30) mmol = 32.5 mmol

Excess volume of AgNO3 is -

Therefore 65 mL of excess AgNO3 is used.