A student prepares an Fe(OH)3 sol by adding 4.00 mL of 0.40 M FeCl3 to boiling water. Assuming complete hydrolysis, FeCl3 + 3H2O -> Fe(OH)3 + 3HCl, find the mass of Fe(OH)3 formed in mg, to the nearest integer. (H = 1, O = 16, Fe = 56)

JEE Main levelNumerical answerDifficulty 2 of 3sc137

A student prepares an $Fe (OH) X_{3}$ sol by adding $4.00 mL$ of $0.40 M$ $FeCl X_{3}$ to boiling water. Assuming complete hydrolysis, $FeCl X_{3} + 3 H X_{2} O Fe (OH) X_{3} + 3 HCl$ , find the mass of $Fe (OH) X_{3}$ formed in mg, to the nearest integer. (H = 1, O = 16, Fe = 56)

Numerical answer type, answer in mg, tolerance 1.

Moles of

FeCl X_{3}

4.00 \times 0.40 = 1.60

mmol. One mole of

FeCl X_{3}

gives one mole of

Fe (OH) X_{3}

. Molar mass of

Fe (OH) X_{3}

56 + 3 (17) = 107 g/mol

. Mass =

1.60 \times 107 = 171.2

mg, which is 171 mg.