Answer Q no. 10 (c,d)

Answer Q no. 10 (c,d) o' an arfic'o with • Which must bo a solution to be plated which carried fhö (iv) the is puro nickel. Toe ions that are attracroa negative electrode and discharged Cal (b) When a mojtön ionic compound is electrolyse metal is always formed at the metal iS formed at (c) Electrolysis ot acidulated water an example on/redox reaction; Reduction/o (201B): 10. Explain the following : ?olution ot cane sugar does not conducti its ions or when What is the Ot suß1huriC 'S Of aniortg of them is e of anion write the 114 (c) (e) (f) good conductor. Hydrochloric acid is a good conductor of electricity During the electrolysis of an aqueous solution NaCl, hydrogen ion is reduced at the cathode not the sodium ion though both Na• and are present in the solution. On electrolysis of dilute copper (II) sulphate solution. copper is deposited at the cathode but hydrogen gas evolves there. Explain why ? When a dilute aqueous solution of sodium chlor& is electrolysed between platinum electrodes, hydrogen gas is evolved at the cathode but metallic sodium is not deposited. Why ? Zinc Can produce hydrogen on reacting With acids but copper cannot. Explain.

Dear Student,

Ans,10.c)

  • Electrolysis of aqueous NaCl: 

Here, NaCl and Water H2O both are present and both dissociate as

NaCl -----------> Na+ + Cl-

H2O--------------> H+ + OH-

Reaction as cathode: Both Na+ and H+ will compete for cathode but reaction with higher E0 is preferred

 Na+ + e- ----------> Na  E0 = -2.71 V  (1)

H++ e- -----------> 1/2 H2   E0 = 0.00 V  (2)

Since, (2) has higher value of E0 So, H2 is product deposited at cathode. 

Note-The eqn 2 can also be written as  H2O + e- --------------> 1/2 H2 + OH-

Hence, Hydrogen ion is reduced at the cathode, and not the Sodium ion.

P.S. kindly post separate questions in separate threads.

Regards

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