The composition of a sample of Wustite is Fe_0.93O_1.00 what percentage of the iron is present in the form of Fe(III)?

Upon mixing 45.0 ml. of 0.25 M lead nitrate solution with 25.0 ml. of 0.10M chromic sulphate solution, precipitation of lead sulphate takes place. How many moles of lead sulphate are formed? Also, calculate the molar concentrations of the species left behind in the final solution. Assume that lead sulphate is completely insoluble.

A 2.0 g sample of a mixture containing sodium carbonate, sodium bicarbonate and sodium suplphate is gently heated till the evolution of CO₂ ceases. The volume of CO₂ at 750 mm Hg pressure and at 298K is measured to be 123.9 ml. A 1.5g of the same sample requires 150 ml. of (M/10) HCl for complete neutralisation. Calculate the % composition of the components of the mixture.

One gram of commercial AgNO₃ is dissolved in 50 ml. of water. It is treated with 50 ml. of a KI solution. The silver iodide thus precipitated is filtered off. Excess of KI in the filterate is titrated with (M/10) KIO₃ solution in presence of 6M HCl till all I^- ions are converted into ICl. It requires 50 ml. of (M/10) KIO₃ solution. 20 ml. of the same stock solution of KI requires 30 ml. of (M/10) KIO₃ under similar conditions. Calculate the percentage of AgNO₃ in the sample.
(Reaction : KIO₃ + 2KI + 6HCl $$\to$$ 3ICl + 3KCl + 3H₂O)