Question

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.

Solution

Correct option is

+ 0.76, – 0.80

 

(a) To predict reaction of zinc with sulphuric acid: 

 If Zn reacts, the following reaction should take place 

          

      

By convention, the cell will be represented as

       

Standard EMF of the cell

          

                = 0 – (–0.76) = + 0.76 volt

Thus the EMF of the cell comes out to be positive.

Hence, the reaction takes place.

(b) To predict the reaction of silver with sulphuric place:

If Ag reacts, the following reaction should take place:

            

By convention, the cell may be represented as

        

                 = 0 – 0.80 = – 0.80 volt

Thus, the EMF of the supposed cell comes out to be negative. Hence, this reaction does not take place.  

SIMILAR QUESTIONS

Q1

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

Q2

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?

Q3

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

Q4

 

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?

Q5

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

Q6

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

Q7

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.

Q8

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.

Q9

 

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?

Q10

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