Chemistry class ix notes 9th class board pattern model paper
Chap-7 Electro chemistry Important questions, if you attempt these question you will get InshaAllah 100% marks.
Chap-7 Electro chemistry
Objective
Part
Choose the right option. 10×1=10
|
|
|
A
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B
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C
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D
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1
|
Which one of the following is not an electrolytic
cell
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Downs cell
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Galvanic cell
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Nelson’s cell
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Both a and c
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2
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The oxidation number of chromium in K2Cr2O7
is:
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+2
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+6
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+7
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+14
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3
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The formula of rust is:
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Fe2O3.nH2O
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Fe2O3
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Fe(OH)3.nH2O
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Fe(OH)3
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4
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Electrolysis of NaCl is done in the cell
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Electrolytic
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Voltaic
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Downs
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Faraday’s
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5
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In dry cell _____ act as cathode:
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Zn cup
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Graphite rod
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Paste
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Steel rode
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6
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An example of weak electrolyte is:
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Glucose
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Aq. NaCl
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HCl
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H2SO4
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7
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Cations are ______ ions.
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Positive
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Negative
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Neutral
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None of these
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8
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The most common example of corrosion is:
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Chemical decay
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Rusting of iron
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Rusting of aluminium
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Rusting of tin
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9
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Spontaneous chemical reactions take place in:
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Electrolytic cell
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Galvanic cell
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Nelson’s cell
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Downs cell
|
|
10
|
In redox reaction between Zn and HCl, the
oxidizing agent is:
|
Zn
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H+
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Cl-
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H2
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Total
Marks= 25
Name______________ Class: 9th Subject: Chemistry
Subjective
Answer
the short questions. 10×2=20
1. Differentiate
between oxidizing and reducing agents.
2. Why
O2 is necessary for rusting?
3. Differentiate
between strong and weak electrolyte.
4. Why
galvanizing is done?
5. Define
corrosion.
6. Where
does the sodium metal is collected in Downs cell?
7. Which
type of chemical reaction takes place in electrolytic cell?
8. What
is the difference between valency and oxidation state?
9. Name
the by-products produced in Nelson’s cell.
10. Define
oxidation-reduction or redox reaction.
Long Questions 5×1=5
1. (a)
What is electroplating? How electroplating of chromium is carried out? 3
(b)
Write down the rules for assigning oxidation state or oxidation number. 2