Answer:
The molar concentration of Fe²⁺ in the original solution is 1.33 molar
Explanation:
Moles of K₂Cr₂O₇ = Molarity x Volume (lit)
= 0.025 x 35.5 x 10⁻³
= 0.0008875
Cr₂O₇²⁻ + 6 Fe²⁺ + 14 H⁺ → 2 Cr³⁺ + 6 Fe³⁺ + 7 H₂O
From equation
1 mole K₂Cr₂O₇ used for the oxidation of 6 moles Fe²
0.0008875 mole K₂Cr₂O₇ used for the oxidation of = = 0.005325 mole of Fe²
Molarity =
Molar concentration of Fe² = = 1.33 molar
So molar concentration of Fe²⁺ in the original solution = 1.33 molar