Question

Calculate the concentration of hypo (Na2S2O3.5H­2O) solution in g dm–3 if 10.0 of this solution decolourised 15 mL of M/40 iodine solution.

Solution

Correct option is

18.6 g dm–3

 

The balanced equation for the redox reaction is

       

For the balanced equation, it is evident that

       2 moles of Na2S2O3 ≡ 1 mole of I2

Applying molarity equation, we have

         

         

   

  

Mol. Mass of Na2S2O3.5H2O = 248 g mol–1

                                = 18.6 g dm–3     

SIMILAR QUESTIONS

Q1

What volume of 0.01 M K2Cr2O7 would be required to oxidize Fe (II) in 50ml of 0.03 M solution of ferrous ammonium sulphate in acidic medium?

Q2

100ml of 0.01 M KMnO4 oxidizes 10ml of H2O2 sample in acidic medium. The volume strength of H2O2 sample is

Q3

A sample of mixture of AO and A2O3 in 2 : 1 molar ratio takes 0.015 mole of K2Cr2O7 to oxidize the sample completely to from  in acidic solution. Millimoles of AO and A2O3 in the sample are respectively

Q4

0.01 mole of Fe3O4 is treated with excess of KI solution in presence of dilute H2SO4 whereby iron is reduced to Fe2+ along with liberation of iodine. What volume of 0.1 M Na2S2O3 will be needed to reduce the librated iodine?

Q5

In which of the following reaction, oxidation number of N remains unchanged?

Q6

 

KMnO4 acts as a strong oxidizing agent in acidic medium. The reaction that occurs is

What will be the effect on the electrode potential of a half-cell represented as  if the concentration of H+ ion is doubled in solution?

Q7

In which of the following oxidation state of phosphours is + 3?

Q8

Determine the volume of M/8 KmnO4 solution required to react completely with 25.0 cm3 of M/4 FeSO4 solution is acidic medium.

Q9

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.

Q10

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.