Question

Iron (III) hydroxide is soluble in acid:

Fe(OH)3(s)3H^+(aq)-->Fe^3^+(aq)+3H2O(l)

a. How many milliliters of 1.00 M HCl are needed to dissolve 1.00 g of iron (III) hydroxide?

b. If you added enough HCl to dissolve the 1.00 g of iron (III) hydroxide and then diluted the solution to 50.0 mL, what would the concentration (molarity) of iron be in the solution?

c. Haw many grams of iron (III) hydroxide can be dissolved in 10.0 mL of 12.0 M HCl?

Answer 1

a. Convert 1.00 g Fe(OH)3 to mols. mols = grams/molar mass.
Use the coefficients in the balanced equation to convert mols Fe(OH)3 to mols H^+.
mols HCl = M x L. You know mols HCl and M HCl, solve for L and convert to mL.

b. M Fe^3+ = mols/L soln
You know mols from part a, L you get from L added from part a + 50 mL(0.050 L).l

c. mols HCl = M x L = 12.0 x 0.01 L = ?
Convert mols HCl to mols Fe(OH)3 and convert that to grams Fe(OH)3