Question # 1

The oxidation number of chromium in K₂Cr₂O₇ is:

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+2

+6

+7

+14

CO2 the oxidation number of C =.

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+1

+2

+3

+4

The formula of rust is:

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Fe₂O₃,nH₂o

Fe₂O₃

Fe(OH)₃-nH₂O

Fe(OH)₃

During the formation of water from hydrogen and oxygen, which of the following does not occur?

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Hydrogen has oxidized

oxygen has reduced

oxygen gains electrons

hydrogen behaves as oxidizing agent

By electrolytic refining of copper , it is ____________ % pure.

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98

99

99.99

100

Which is used for industrial manufacture of NaCI?

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Daniel cell

Down's cell

Nelson's cell

None of these

In metal hydrides, the oxidation number of hydrogen is

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+1

-1

+2

-2

Copper extracted from its ore is ____________ % pure.

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98%

99%

96%

Nil

____________ is an irreversible cell.

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Dry cell

Chargeable cell

Zn cell

None of these

Oxidation means

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Gain of oxygen

Removal of oxygen

Gain of hydrogen

Gain of electrons

Which one is strong electrolyte ?

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NH4OH

NaOH

a & b

Nil

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