Q.1. Write the differences between electrochemical cell and electrolytic cell ?
Ans:- Electrochemical Cell: (i) It converts chemical energy into electrical energy.
(ii) Salt bridge is used.
(iii) Anode works as -ve charge and Cathode works as +ve charge.
Electrolytic Cell: (i) It converts electrical energy into chemical energy.
(ii) Salt bridge is not used.
(iii) Anode works as +charge and Cathode works as -ve charge.
Q.2. What is standered electrode potential (E⁰) ?
Ans:- The potential difference developed between the metal electrode and the electrolyte of unit molarity (1M) at 1 atm pressure and 25⁰C (298k) is called standard electrode potential.
Q.3. Write Faraday’s laws of electrolysis ?
Ans:- First law:- Mass of substance deposited at an electrode is directly proportional to amount of charge passed through solution.
Second law:- If same quantity of charge is passed through different electrolytic solution then substance will be equal.
Q.4. What is cell constant ?
Ans:- The ratio of the distance between the electrodes divided by the area of cross section of the electrode is called as cell constant.
Q.5. What is Salt bridge ? What are its uses ?
Ans:- In electrochemistry it is a laboratory device used to connect the oxidation and reduction half-cells of a galvanic cell (voltaic cell) a type of electrochemical cell. Salt bridge usually come into two types: glass tube and filter paper.
It is used in voltaic cell. It completes the circuit. It eliminates liquid junction potential.
Q.6. What is a primary cell ? Give an example.
Ans:- The cell which produces electrical energy by irreversible chemical reaction within the cell is called a primary cell. The primary cells cannot be charged for repeated use. Example : Dry cell, Daniell cell.
Q.7. Define Electrochemical equivalent (Z) ?
Ans:- If I = 1Ampere and t = 1sec
Thus, the electrochemical equivalence may be defined the amount of the substance deposited by passing 1 Ampere of current for 1 sec or by passing 1 Coulomb of charge through the electrolyte.
Q.8. What is lead storage cell ?
Ans:- In these cells, the electrical energy stored in the form of chemical energy . therefore this cells are called lead storage cells.
Q.9. Why does the conductivity of a solution decrease with dilution ?
Ans:- The conductivity of a solution is related with the number of ions present per unit volume of the solution. When the solution is diluted, the number of ions decreases. Hence, conductivity on a specific conductance of the solution also decreases.
Q.10. Why does conductivity of solution of electrolyte increases by heating ?
Ans:- On increasing temperature the average kinetic energy increases in solution and hence electrical conductivity increases.