Chemistry For Class IX (New Book ) - Chapter No. 7 - Electrochemistry - Multiple Choice Questions And Fill In The Blanks

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Chapter No.7 - Electrochemistry
MCQs And Fill In The Blanks
Text Book Exercise

SECTION- A: MULTIPLE CHOICE QUESTIONS
Tick Mark (✓) the correct answer

1. Alloy of Cu - Sn is called
(a) Brass
(b) Bronze
(c) Monel
(d) Bell metal ✓

2. Which one is Alloy.
(a) Graphite
(b) Mercury
(c) Steel ✓
(d) Water

3. Value of 1 Farady is equal to:
(a) 9.65 C
(b) 9650 C
(c) 96500 C ✓
(d) 965 C

4. Which one is non electrolyte.
(a) Aqueous HCl
(b) Aqueous NaCl
(c) Molten KCl
(d) Urea ✓

5. Which one is oxidizing agent.
(a) Al
(b) H₂S
(c) Cl₂ ✓
(d) NaH

6. Which one is reducing agent.
(a) H₂S0₄
(b) HNO₃
(c) Al ✓
(d) I₂

7. Which one forms weak electrolyte solution with water:
(a) HCl
(b) KOH
(c) NaCl
(d) CH₃COOH ✓

8. In Daniel cell ____ is used as cathode.
(a) Zn
(b) Cu ✓
(c) Sn
(d) Pb

9. 1 g equivalent weight of Al is equal to:
(a) 9 g ✓
(b) 27 g
(c) 54 g
(d) 1 g

10. Which one is correct statement.
(a) Oxidation occurs at cathode.
(b) Reduction occurs at anode
(c) Reduction occurs at cathode ✓
(d) Ions lose electrons at cathode.

FILL IN THE BLANKS:

1. Oxidation is the loss of electron by chemical substance.
2. Reduction is the gain of electron by chemical substance.
3. An electrolyte consists of free moving ions and conduct electricity.
4. An electrode is an electrical conductor.
5. The electrode at which oxidation occurs is called anode.
6. The electrode at which reduction occurs is called cathode.
7. Electrolysis is a process of migration of ions towards cathode and anode when current passes through en electrolyte.
8. Oxidizing agent helps in oxidation by accepting electrons.
9. Reducing agent helps in reduction by losing electrons.
10. A galvanic cell converts chemical energy into electrical energy.
11. An electrolytic cell uses electrical energy to derive a non spontaneous reaction.
12. Corrosion of iron is called rusting.
13. Corrosion of metal can be prevented by alloying, paint or electroplating metal by zinc, tin, silver, chromium etc.
14. An alloy is a mixture of metal with metal or metal with non metal.
15. Digital watches, calculators, cars and mobile phones. powered by batteries or dry cells.
16. 24 karat gold is called 100% pure gold.
17. The formula of rust is (iron (III) oxide) (Fe₂O₃.nH₂O)

CONCEPT MAP

Point To Remember:

Reaction: Oxidation reaction

• Status: Loss of Electron
• Electrode: Anode (positive electrode)
• Ion on Anode: Anion
• Agent: Reducing agent (Cation)

Reaction: Reduction reaction

• Status: Gain of Electron
• Electrode: Cathode (negative electrode)
• Ion on Cathode: Cation
• Agent: Oxidizing agent (Anion)

Some Important Alloys With Their Components And Applications

Name Of Alloy	Components	Applications
Bell Metal	Cu-Sn	Casting of bell
Brass	Cu-Zn	Door nobs and hand rails due to antibacterial nature, Hose nozzles, Stamping dies.
Bronze	Cu-Zn-Sn	Coins, medals, tools, etc.
Monel	Ni-Cu-Fe	Corrosion resistant containers
Duralumin	Al-Cu-Mg-Ni	Boat, Aircraft etc.
Solder	Sn-Pb-Cu-Sb	Joining electrical components into circuits
Alnico	Fe-Al-Ni-Co	Magnets used in loud speakers
Amalgam	Hg-Ag-Cu-Zn	Dental filling
Cupronickel	Cu-Ni-Mn	Coins
Pewter	Sn-Cu-Pb-Sb-Bi	Ornaments
Sterling silver	Ag-Cu	Cutlery set, Medical tools
White Gold (18 Karat)	Au-Pb-Ag-Cu	Jewelry
Red Gold (18 K)	Au-Cu	Jewelry
Yellow Gold (22 K)	Au-Ag-Cu-Zn	Jewelry

Elements Use In Alloys with Their Symbols:

• Ag = Silver (Argentum)
• Al = Aluminium
• Au = Gold (Aurum)
• Bi = Bismuth
• Co = Cobalt
• Cu = Copper
• Fe = Iron (Ferrum)
• Hg = Mercury (Hydragyrum)
• Mg = Magnesium
• Mn = Manganese
• Ni = Nickel
• Pb = Lead (Plumbum)
• Sb = Antimony (Stibium)
• Sn = Tin (Stannum)
• Zn = Zinc