Details
1) A mass of 9.80g of ammonium iron (II) sulfate crystals (NH4)2 SO4 . x H2O was dissolved in dilute sulfuric acid and the resulting solution was made up to 250cm3 in a volumetric flask. 25cm3 of this solution was titrated against 0.021 M KMnO4 solution. The average titration figure was 23.85cm3 , Calculate the value of x in the above formula. 2. A chemist dissolved 7.84g of ammonium iron (II) sulfate,(NH4)2SO4 . FeSO4.xH2O in dilute sulfuric acid and made up the solution to 250cm3 with distilled water, 25cm3 of this solution required 20cm3 of 0.02 M potassium manganate (VII) (potassium permanganate) for complete reaction according to the equation : 5Fe2+ + MnO4 - + 8H+ →5Fe + Mn2+ 4H2O (i) Why was dilute sulfuric acid used in making up the iron (II) salt solution? (ii) Find the concentration, in moles per litre, of Fe2+ ions in the solution.(iii) Find the value of x. (iv) Show clearly any changes in oxidation numbers which have occurred in the reaction.
Stats
- Recommendations n/a n/a positive of 0 vote(s)
- Views 269
- Comments 0