3.1 Define electrochemistry

Solution

The branch of chemistry which deals with the study of the conversion of chemical energy into electrical energy or vice versa and their mutual relationship is referred to as electrochemistry

3.2 Define and explain the following terms:
(a) Strong electrolyte
(b) weak electrolyte
(c) non electrolyte

Solution

(a) Strong Electrolyte :
The electrolyte which dissociates almost completely into ions in solutions are called strong electrolyte
The degree of dissociation of these electrolytes is almost equal to 1
Example :
Strong acids : HCl , HNO₃ , H₂SO₄
Strong base : NaOH , KOH , Ba(OH)₂
(b) Weak Electrolyte :
The electrolyte which do not dissociate much in aqueous solution are called weak electrolytes
Due to partial dissociation the degree of dissociation of these electrolytes is less than 1
Example :
Organic acids : acetic acid , oxalic acid , benzoic acid
Organic bases : CH₃NH₂ , C₂NH₂
(c) Non-electrolyte :
Glucose , a sugar with the chemical formula C₆H₁₂O₆ is a example of non-electrolyte. It dissolves readily in water because it does not dissociate inside the solution into ions it is Considered as non-electrolyte
Another example : Ethanol.

3.3 Sort out strong electrolytes weak electrolytes and non electrolytes among the following:
NH₄Cl , CH₃OONa , NaCl , CH₃COOH , HCN , NH₄OH , Urea , Sucrose

Solution

-> Strong electrolyte = NH₄Cl , CH₃OONa , NaCl
-> Weak electrolyte = CH₃COOH , HCN , NH₄OH
-> Non-electrolyte = Urea , Sucrose

3.4 What do you understand by electrolytic conduction ? In what way it is different from metallic conduction

Solution

The ease flow of current through an electrolytic solution is called electrolytic conductance.
Electrolytic conduction is due to the movement of ions and it increases with the rise in temperature
It is different from metallic conduction
-> Due to the movement of electrons
-> It does not involve any transfer of matter.

3.5 Discuss the factors on which electrolytic conduction depends

Solution

Factors affecting Electrolytic conductance
(i) The Concentration of Ions on the solution
The Conductance of the solution varies with the ion concentration the conductivity of electrolytes will increase with the increase in the concentration of ions
(ii) Types of electrolytes : Strong electrolytes gets ionized Completely in the Solution where as weak electrolyte do not.
(iii) Temperature :
Ions should dissolves in the solution at given temperature. So at higher temperatures the solubility is more.
(iv) Type of solvent :
Highest the polarity of the solvent type the higher the conductivity.