Final answer:
The percentage of tin in the substance, the reaction between tin(II) and dichromate is 86.48%, though this value does not match any of the provided options.
Step-by-step explanation:
To calculate the percentage of tin in the substance, we must first establish the balanced chemical equation representing the redox reaction between tin in the +2 state and dichromate. In an acidic solution, the reaction is as follows:
3 Sn₂⁺ + 2 Cr₂O₇²⁻ + 24 H⁺ → 3 Sn₄⁺ + 4 Cr₃⁺ + 12 H₂O
Based on the given data, the dichromate solution was prepared by dissolving 1.226 g of K₂Cr₂O₇ in enough water to give a volume of 250.00 cm³. We can calculate the molarity of this solution to determine the moles of dichromate:
Molarity = amount of substance (mol) / volume of solution (L)
= (mass (g) / molar mass (g/mol)) / volume (L)
The molarity of the dichromate solution is:
1.226 g K₂Cr₂O₇ / 294.18 g/mol (molar mass of K₂Cr₂O₇) = 0.00417 mol / 0.25 L = 0.01668 M
The moles of dichromate that reacted are
0.01668 mol/L * 0.02390 L = 0.0003987 mol.
From the stoichiometry of the balanced equation, 3 moles of Sn₂⁺ react with 2 moles of Cr₂O₇²⁻, which gives us:
Moles of Sn₂⁺ = (3/2) * moles of Cr₂O₇²⁻
= (3/2) * 0.0003987 mol
= 0.00059805 mol
To convert moles of Sn to grams:
0.00059805 mol * 118.71 g/mol (molar mass of Sn)
= 0.07100 g of Sn
Finally, to determine the percentage of tin in the substance:
% Tin = (mass of Sn in sample / mass of sample) * 100
= (0.07100 g / 0.0821 g) * 100
= 86.48%
None of the given options matches with the calculated percentage; therefore, there might be a mistake in the question statement or the options provided. The correct answer is not listed.
Your question is incomplete but most probably your full question was
A sample of a substance who only oxidizable material is tin in the +2 state, is titrated with a dichromate solution that was prepared by dissolving 1.226g of K₂Cr₂O₇ in enough water to give a volume of 250.00cm³. A 0.0821g sample of the substance required a volume of 23.90cm³ of the titrant to reach the equivalence point . The product of the oxidation of the tin in the +2 state is to tin in the +4 state . The reduction product of the dichromate , is chromium in the +3 state. Calculate the % of tin in the substance . ( NB: Assume the reaction takes place in an acidic medium.) a) 22.5% b) 45.0% c) 50.0% d) 55.5%