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How does molar conductivity vary with concentration for (i) weak electrolyte and for (ii) strong electolyte? Give reasons for these variations.


(i) Weak electrolytes: When the concentration of weak electrolyte becomes very low, its degree of ionisation rises sharply. There is sharp increase in the number of ions in the solution. Hence, the molar conductivity of a weak electrolyte rises steeply at low concentration.
(ii) Strong electrolytes: The molar conductivity of a strong electrolyte decreases slightly with the increase in concentration. This decrease is due to the increase in interionic attractions as a result of greater numbr of ions per unit volume. With dilution, the ions are far apart, inter ionic attractions become weaker and conductance increases.

(i) Weak electrolytes: When the concentration of weak electrolyte bec

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State and explain Faraday's law of electrolysis?

Faraday's first law. The amount of substance produced at an electrode during electrolysis is directly proportional to the quantity of electricity passed through the electrolyte.

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Write anode and cathode reactions from electrolysis of water. How much charge will be transported for the decomposition of 3.6 g of H2O? [F = 96500 C mol–1]

At cathode: 4H++4e- 2H2(g)
At anode: 2H2OO2+4H++4e-

36 g of H2O requires 4×96500 C

3.6 of H2O requires 4×9650036×3.6 = 38600 C.

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What is a mercury cell? Give the electrode reactions?


A mercury battery (also called mercuric oxide battery, or mercury cell) is a non-rechargeable electrochemical battery, a primary cell. Mercurybatteries use a reaction between mercuric oxide and zinc electrodes in an alkaline electrolyte.

Mercury cell is a new type of dry cell. It consists of
Anode:   Zinc-mercury.
Cathode: Paste of HgO and carbon
Electrolyte: Paste of ZnO in KOH.

The reactions are:
Anode:
Zn (amalgam) + 2OH-ZnO(s)+H2O + 2e-
 
At cathode:
HgO+H2O + 2e-  Hg(l)+2OH-
           
Overall reaction:
Zn(amalgam)+HgO(s)ZnO(s)+Hg(l)
        
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What are fuel cells? Write the reaction of a oxygen hydrogen fuel cell.

Fuel cell: A galvanic cell in which the reactants are continuously fed into the cell and the products are continuously removed is called a fuel cell.
The most important fuel cell is hydrogen oxygen fuel cell.
The reactions taking place in this fuel cell are
At cathode:
                   straight O subscript 2 plus 2 straight H subscript 2 straight O left parenthesis straight l right parenthesis plus 4 straight e to the power of minus rightwards arrow 4 OH to the power of minus
space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space straight E to the power of 0 subscript cathode space equals space 1.229 space straight V
At anode:
                  2 straight H subscript 2 left parenthesis straight g right parenthesis plus 4 OH to the power of minus space rightwards arrow space 4 straight H subscript 2 straight O plus 4 straight e to the power of minus
space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space straight E to the power of 0 subscript cathode space equals space 0.00 space straight V
Net reaction:

Fuel cell: A galvanic cell in which the reactants are continuously fe


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