ECAT Pre Engineering Chemistry Chapter 10 MCQ Test With Answer

In an electrolytic cell, the electrons flow from :

• Cathode to anode or opposite A
• Cathode to anode B
• Anode to cathode C
• Random flow D

The equivalent conductivity of 0.1 M week acid is 100 times less than at infinite dilution. The degree of dissociation is

• 100 A
• 10 B
• 0.01 C
• 0.001 D

Metals which are above SHE in electrochemical series

• Can liberate H₂from acid A
• Cannot liberate H₂from acid B
• Cannot always liberate H₂from acid C
• None of these D

The reduction potential to copper electrode is +0.34 V and that of Zn electrode is -0.76 V. when these two are coupled the e.m.f. of the cell is

• -0.42 V A
• +0.42 B
• -1.10 V C
• +1.10 V D

In the electrolysis of fused bauxite (Al₂O₃2H₂O) with fused Cryolite (Na₃AlF₆) using carbon rods as anode. The product obtained at cathode is

• Na metal A
• F₂gas B
• Al metal C
• O₂gas D

A cell constant is generally found by measuring the conductivity of aqueous solution of

• BaCl₂ A
• KCl B
• NaCl C
• MgCl₂ D

An electrochemical cell is based upon

• Acid-base reaction A
• Redox reaction B
• Nuclear reaction C
• None of the above D

The cell which generates electricity as a result of spontaneous oxidation-reduction reaction is called

• Electrolytic cell A
• Nelson's cell B
• Galvanic cell C
• Down's cell D

A cell in which electric current is produced as a result spontaneous redox reaction is called :

• Dry cell A
• Electrolytic cell B
• Galvanic cell C
• Standard cell D

The two half cells of a galvanic cell are connected by

• Ammeter A
• Salt bridge B
• Hydrogen electrode C
• Copper electrode D

The process of electrical coating of one metal on another to protect, decorate or to have greater resistance to corrosion is called

• Electroplating A
• Electrolysis B
• Conduction C
• Induction D

Which statement is incorrect for NICAD battery

• The electrolyte is alkali A
• Cd acts as anode B
• MnO₂acts as electrolyte C
• NiO₂acts as cathode D

• Zn A
• H B
• S C
• O D

When aluminium electrode is coupled with copper electrode in a galvanic cell :

• Reduction takes place at aluminium electrode. A
• Oxidation takes place at copper electrode. B
• Reduction takes place at copper electrode. C
• Both (a) and (c) D

The voltaic or galvanic cells which cannot be recharged are called

• Primary cells A
• Secondary cells B
• Infinite cells C
• Fuel cells D

A certain current liberate 0.5 g of hydrogen in 2 h. How many grams of copper can be liberated by the same time in a copper sulphate solution?

• 12.7 gm A
• 15.9 gm B
• 31.8 gm C
• 63.5 gm D

The amount of electricity that can deposit 108 g of silver from silver nitrate solution is

• 1 ampere A
• 1 coulomb B
• 1 faraday C
• 2 ampere D

The best electrode used in salt bridge is KCl. Which other electrolyte an also be used for the purpose :

• NaCl A

• NH₄NO₃

  B

• KNO₃

  C

• NaNO₃

  D

When quantity of electricity passed is one faraday then the mass deposited at the electrode is equal to

• One gm, atomic weight A
• One gm, Equivalent B
• Eletrochemical equivalent C
• None of the above D

While balancing an equation by ion electron method, the number of oxygen atoms are balanced by

• OH^- A
• H₂O B
• O₂ C
• H⁺ D

A half reaction can be defines as :

• It always occurs at cathode. A
• Involves only half of a mole of electrolyte. B
• Occurs at one of the electrode. C
• Goes only half way to completion. D

During redox reaction an oxidizing agent

• Gains electrons A
• Is oxidized B
• Loses electrons C
• Hydrolysed D

Most metals are conductors of electricity because of the :

• Light weight. A
• Immobility of the electrons. B
• Lustrous surfaces C
• Relatively free movement of their electrons D

• Adding H₂O and H⁺ions A
• Adding OH^-ions B
• Adding O²molecules C
• Adding O atoms D

Same amount of electric current is passed through solutions of AgNO₃and HCl. If 1.08 g of silver is obtained in the first case, the amount of hydrogen liberated as S.T.P in the second case is

• 112 cm³ A
• 22400 cm³ B
• 224 cm³ C
• 1.008 g D

The conversion of chemical energy into electrical energy requires :

• Electrolytic cell A
• Galvanic cell B
• Voltaic cell C
• Both (b) and (c) D

The standard EMF of Daniel cell is 1.10 volt. The maximum electrical work obtained from the Daniel cell is

• 212.3 kJ A
• 175.4 kJ B
• 106.15 kJ C
• 53.07 kJ D

Pure water does not conduct electricity because it

• Has low boiling point A
• Is almost unionized B
• Is neutral C
• Is readily decomposed D

In electrolysis of NaCl when Pt electrode is taken then H₂is liberated at cathode while with Hg cathode it forms sodium amalgam

• Hg is more inert than Pt A
• More voltage is required to deduce H⁺at Hg than Pt B
• Na is dissolved in Hg while it does not dissolve in Pt C
• Conc. of H⁺ions is larger when Pt electrode is taken D

Ionization is the process in which ionic compounds when fused or dissolved in water split up into charged particles called :

• Atoms. A
• Electrons. B
• Protons . C
• Ions D