CHAPTER-18
Ionic Conduction
Text Book Question and Answers
I. Answer the following
1. Write any two example for metallic conductors
Iron, Aluminium, Copper, Mercury, Gold, Silver
2. What is an electrolyte?
The Chemical substance that conducts electricity in aqueous state is known as an electrolyte
3. What is a voltameter?
Voltameter is a device used to measuring electricity in the circuit.
4. When electrodes are dipped in aqueous sodium chloride solution the bulb grows brightly, why?
Because the solvated sodium and chloride ions carry charges through the solution completing the circuit and allow the bulb to glow.
5. Identify the strong electrolyte in the following
1) Acid diluted water(Acidified water)
2) Dilute acetic acid
3) Sugar solution in water
4) Distilled water
Acid diluted water(Acidified water)
6. What is electrolysis?
The production of chemical change by passing electric current through an electrolyte resulting in the movement of ions towards the electrodes is known as electrolysis.
7. Name the cation in common salt solution.
The cation in common salt solution is sodium ion.
8. Distinguish between cation and anion?
When an electric field is applied to an electrolyte,
The negatively charged particles which move towards anode are called anions.
The positively charged particles which move towards the cathode are called cations.
II. Four alternatives are given to each of the following incomplete statement / question. Choose the right answer
1. E.C.E implies
(a)electro correlation equivalent
(b)electro chemical equivalent
(c)chemical equivalent
(d)endochemical constant
Answer: (b)electro chemical equivalent
2. Substances which conduct electricity in liquid or molten state is called
(a)electrolyte (b)non Electrolyte (c)conductor (d)insulator
Answer: (a)electrolyte
3. In a solution of dissociation is complete then the solution is a
(a)weak electrolyte (b)non electrolyte (c)strong electrolyte (d)neutral electrolyte
Answer: (c)strong electrolyte
4. The method of coating one metal layer on another is called
(a)electrotyping (b)electro printing (c)electro plating (d)electro polishing
Answer: (c)electro plating
5. The article to be electroplated is taken as
(a)anode in the voltameter (b)cathode in the voltameter
(c)it is placed in between anode and cathode of the voltameter (d)as an electrolyte
Answer: (b) cathode in the voltameter
6. The theory of dissociation was formulated by
(a)Arrehinius (b)C.V. Raman (c)Einstein (d)Newton
Answer: (a)Arrehinius
7. Chemical equivalent of a substance is given by
(a)atomic mass x valency (b)atomic mass + valency
(c)atomic mass / valency (d)atomic mass – valency
Answer: (c) atomic mass / valency
III. Answer the following questions
1. Define electrolysis
The production of chemical change by passing electric current through an electrolyte resulting in the movement of ions towards the electrodes is known as electrolysis.
2. Draw a neat labelled diagram voltameter
3. Name the three types of electrolytes. Give an example for each.
The three types of electrolytes are
i. Strong electrolyte
Eg: Sodium chloride solution
ii. Weak electrolyte
Eg: Dilute acetic acid
iii. Non electrolyte
Eg: sugar solution
4. Explain Arrehinius theory of dissociation.
Arrhenius theory of electrolytic dissociation states that
The molecules of an electrolyte in aqueous solution break into ions and freely move about in the bulk of the solution
5. E.C.E. of gold is 0.0006812 what do you mean this?
E.C.E of gold is 0.0006812 means 0.0006812gms mass of gold is liberated by unit current in unit time
6. State Faraday’s laws of electrolysis.
First law – The mass of substance deposited or collected at either electrode during electrolysis is proportional to the current and to the time.
m a It m is mass, I is current, t is time.
m = ZIt but Q = It
m = ZQ
Z is the constant of proportionality
Second law – The masses of different substance liberated by the same quantity of electricity are proportional to their chemical equivalent.
MA/MB = EA / EB = F
M is mass of the substance
E is Chemical Equivalent
F is Faraday’s constant
IV. Match the following
1. Pressure – pascal(Pa)
2. Weak electrolyte – Acetic acid
3. Strong electrolyte – NaCl
V. Problems
1. How much time is required to deposit 1.10 gm of copper by passing 0.5 ampere of current. If E.C.E. of copper is 0.00033 gm/coulomb
Solution:
Z = 0.00033 gm/coulomb
I = 0.5 A
m = 1.10 gm.
t = ?
W.K.T.
m = ZIt
t = m / ZI
t = 1.10 / 0.00033 X 0.5
t = 1.10 / 1.65 X 10-4
t = 0.66666 X 10-4
t = 6666.66 seconds
2. To deposit 0.54 gm copper on cathode in a copper voltameter how much quantity of electricity is required
Solution:
m = 0.54gm
Z = 0.00033gm/coulomb
Q = ?
m = ZQ
Q = m/Z
Q = 0.54 / 0.00033
Q = 1636.36 coulomb.
3. Silver voltameter and copper voltameter are connected in series. The amount of silver and copper deposited are 0.31gm and 0.091gm respectively. If the E.C.E. of copper is 0.00033 gm/coulomb. Calculate the E.C.E. of silver.
Solution:
Ms = 0.31gm
Mc = 0.091gm
Ec = 0.00033gm/coulomb.
Es = ?
Ms/Mc = Es/Ec
0.31 / 0.568 = Es / 0.00033
Es = 0.31 X 0.00033 / 0.568
Es = 1.801 X 10-4
Es = 0.0001801gm/coulomb.
Additional Questions
1. Why is electronic conduction is considered to be a physical change?
Electronic conduction is considered to be a physical change as there is no change in the property of the conductor.
2. Which change of Electrolytic conduction
Electrolytic conduction is a chemical change.
3. What is an Electrolytic solution?
When direct current is passed through certain aqueous solution (Sodium chloride), chemical reaction occurs, such solution are called Electrolytic Solutions.
4. Name the two types of Conduction of Electricity.
i. Metallic Conduction ii. Electrolytic Conduction
5. Differentiate between metallic conduction and electrolytic condution.
| Metallic Condution | Electrolytic condution |
| It is physical change | It is a chemical change |
| Only electrons conduct electricity | Positive as well as negative ions conduct electricity |
| All metals and metallic alloys show metallic conduction | Ionic compounds show electrolytic conduction in aqueous solution. |
6. What is strong and weak electrolytes? Give an example.
Electrolytes that dissociate almost completely are called strong electrolytes. They conduct electricity better.
Eg: Sodium Chloride, Copper sulphate, HCL, Nitric acid, Sulphuric acid,
Electrolytes that dissociate feebly are called weak electrolytes. They conduct electricity partially.
Eg: acetic acetic acid, phosphoric acid, formic acid, carbonic acid.
7. Define Faraday’s constant.
Faraday’s constant is the ration of chemical equivalent to electrochemical equivalent. Its value is 96.500 coulomb/mole. (E/Z = F)
8. What is an ion?
Electrolytes contain charged group of atoms. These charged group of atoms are known as Ions.
9. What is electroplating?
To give the articles made of one metal a coating of another metal either to improve the appearance or to protect it against rusting and tarnishing is called electroplating.
10. What is electro polishing
The metal is removed from the anode by the action of current the elevated anode portion is removed which dissolves in the electrolyte the result an anode is electro polished.
11. Mention the applications of electrolysis.
i. Electroplating
ii. Purification of metals
iii. Electro polishing
iv. Electro typing
v. Decomposition of salts
vi. Manufacturing of chemicals like caustic soda.
Chemical equivalent = Atomic Mass / Valency
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