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Electrochemistry

13 free MDCAT Chemistry MCQs on Electrochemistry (PM&DC syllabus), each with the answer, an explanation and the textbook line it comes from. Tap to check, no sign-up.

MDCAT (Pakistan)ChemistryPre-medical (Grade 12)13 questions

Tap an answer to check it · 13 questions

  1. Question 1

    The mass of a substance liberated at an electrode when one coulomb of electricity is passed is its:

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    Answer: C) Electrochemical equivalent

    Z in W = ZQ (Faraday's first law). Source: Chemistry 11 KPK (taleem360.com), p. 382.

  2. Question 2

    The oxidation number of Cr in K2Cr2O7 is:

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    Answer: C) +6

    2(+1) + 2x + 7(-2) = 0, so 2x = 12 and x = +6. Source: Chemistry 11 KPK (taleem360.com), p. 365.

  3. Question 3

    A cell in which a non-spontaneous redox reaction is carried out by passing an electric current is a/an:

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    Answer: A) Electrolytic cell

    Galvanic (voltaic) cells such as the Daniell cell run spontaneous reactions. Source: Chemistry 11 KPK (taleem360.com), p. 378.

  4. Question 4

    Zinc is the anode in a Daniell cell but the cathode when coupled with aluminium, because the reduction potential of zinc is:

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    Answer: B) Higher than aluminium

    Zn (-0.76 V) is above Cu (+0.34 V) but below Al (-1.67 V); the higher reduction potential is the cathode. Source: Chemistry 11 KPK (taleem360.com), p. 378.

  5. Question 5

    In terms of oxidation number, oxidation is:

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    Answer: C) An increase in oxidation number

    Loss of electrons raises the oxidation number. Source: Chemistry 11 KPK (taleem360.com), p. 364.

  6. Question 6

    An oxidizing agent:

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    Answer: D) Gets reduced itself

    It gains electrons and its oxidation number decreases (e.g. Cl2 0 -> -1). Source: Chemistry 11 KPK (taleem360.com), p. 366.

  7. Question 7

    The oxidation number of an element in its free state is:

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    Answer: A) Zero

    e.g. H2, O2, Na metal. Source: Chemistry 11 KPK (taleem360.com), p. 364.

  8. Question 8

    In an electrochemical cell, oxidation takes place at the:

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    Answer: B) Anode

    Reduction takes place at the cathode. Source: Chemistry 11 KPK (taleem360.com), p. 391.

  9. Question 9

    Zinc displaces copper from CuSO4 solution because zinc has a:

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    Answer: C) Lower reduction potential

    Zn (-0.76 V) lies above Cu (+0.34 V) in the series and gives electrons to Cu2+. Source: Chemistry 11 KPK (taleem360.com), p. 378.

  10. Question 10

    In Nelson's cell for the electrolysis of brine, the NaOH formed is collected at the:

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    Answer: D) Bottom of the cell

    Cl2 is released at the graphite anode and H2 at the perforated steel cathode. Source: Chemistry 11 KPK (taleem360.com), p. 380.

  11. Question 11

    Chemically, the rust on iron is:

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    Answer: C) Hydrated iron(III) oxide

    Fe2O3.xH2O; it is porous, so rusting continues. Source: Chemistry 11 KPK (taleem360.com), p. 388.

  12. Question 12

    Galvanizing protects iron by coating it with:

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    Answer: D) Zinc

    Coating with tin is called tinning. Source: Chemistry 11 KPK (taleem360.com), p. 388.

  13. Question 13

    In electroplating, the article to be plated is made the:

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    Answer: A) Cathode

    Metal ions are reduced and deposited on the cathode; the pure metal is the anode. Source: Chemistry 11 KPK (taleem360.com), p. 391.

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