Which will be the proper alternative in place of A in the following equation.


Correct option is



The balanced equation is:


Thus, A is Sn4+.



0.5 g of an impure sample of oxalate was dissolved in water and the solution made to 100 ml. On titration 10 ml of this solution required 15 ml of N/20 KMnO4 solution. Calculate the percentage of pure oxalate in the sample.


Predict whether zinc and silver react with 1 M sulphuric acid to give out hydrogen or not. Give that the standard potentials of zinc and silver are – 0.76 volt and +0.80 volt respectively.



Can a solution of 1 M copper sulphate be stored in a vessel made of nickel metal? Given that


or Is it possible to store copper soulphate solution in a nickel vessel?


0.2 of sample H2O2 reduced 20 ml of 0.1 M KMnO4 solution in acidic medium. What is the percentage purity of H2O2?


16.6 g of pure potassium iodide was dissolved in water and the solution was made up to one litre. V cm3 of this solution was acidified with 20 cm3of 2 M HCl. The resulting solution required 10 cm3 of decinormal KIO3for complete oxidation of I ions to ICl. Find out the value of V.


Both  (aq) can be used to titrate Fe2+ (aq). If in a given titratoion, 24.50 cm3 of 0.1 M  were used, then what volume of 0.1 M  solution would have been used for the same titration?


1.1 g of a sample of copper ore is dissolved and Cu2+ (aq) is treated with KI. The iodine thus liberated required 12.12 cm3 of 0.1 M Na2S2O3solution for titration. What is the percentage of copper in the ore?


Oxidation number of sodium in sodium amalgam is



In the given reaction,


X, Y, Z are


Number of moles of K­Cr2O7 reduced by 1 mole of Sn2+ is