Precipitation Reaction

Question

In a precipitation reaction between FeCl₂(aq) and LiOH(aq), 11.9 mL of 0.210 M FeCl₂(aq) completly reacted with 37 mL of LiOH(aq). What was the molarity of LiOH(aq)?

FeCl₂(aq) + 2 LiOH(aq)  →  Fe(OH)₂(s) + 2 LiCl(aq)

Note: Insert only the numerical value of your answer with three decimal places (do not include the units or chemical in your answer).

Answer 1

FeCl2(aq) + 2 LiOH(aq)  →  Fe(OH)2(s) + 2 LiCl(aq) ... balanced equation

moles FeCl2 = 0.0119 L x 0.210 mol/L = 0.002499 moles

moles LiOH = 0.002499 mol FeCl2 x 2 mol LiOH / mol FeCl2 = 0.004998 moles

Molarity (moles/L) of LiOH = 0.004998 mol/0.037 L = 0.135 M (to 3 sig. figs.)