ECAT Pre Engineering Chemistry Chapter 10 MCQ Test With Answer

During redox reaction an oxidizing agent

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

When a metal is dipped in 1 molar of its solution at 298 K. then potential set up is called

• Standard electrode potential A
• Electric charge B
• Ionization potential C
• Electroplating D

When fused PbBr2 is electrolyzed :

• Lead appears at anode. A
• Lead appears at cathode. B
• Bromine appears at cathode. C
• Lead appears at both electrodes. D

When fused PbBr₂is electrolyzed

• Bromine appears at he cathode A
• Lead is deposited at the cathode B
• Lead appears at the anode C
• None of these happens D

Best way to prevent rusting of iron is by

• Making iron cathode A
• Putting it in saline water B
• Both of these C
• None of these D

Purification of an impure copper is made by electrolytic cell, in which impure copper is anode and pure copper is cathode, and the electrolyte used is

• H₂SO₄ A
• CuSO₄ B
• ZnSO₄ C
• Na₂SO₄ D

For spontaneity of a cell, which is correct?

• ΔG = 0,ΔE = 0 A
• ΔG = -ve ,ΔE = 0 B
• ΔG = +ve ,ΔE = 0 C
• ΔG = -ve D

Which of the following yield both hydrogen and chlorine on electrolysis:

• Electrolysis of acidified water. A
• Electrolysis of molten NaCl B
• Electrolysis of aqueous NaCl C
• Electrolysis of saline water D

The number of coulombs required for the deposition of 107.870 g of silver is

• 96500 A
• 48250 B
• 193000 C
• 10000 D

A standard hydrogen electrode is used as standard electrode of which electrode potential is arbitrarily taken as

• +1 A
• -1 B
• 0.1 C
• Zero D

In KO₂the oxidation state of oxygen is

• -2 A
• -1 B
• +1/2 C
• -1/2 D

The specific conductance of a 0.1 N KCl solution at 23°C is 0.012 ohm^-1cm^-1. The resistance of cell containing the solution at the same temperature was found to be 55 ohm. The cell constant will be

• 0.142 cm^-1 A
• 0.66 cm^-1 B
• 0.916 cm^-1 C
• 1.12 cm^-1 D

Cell potential depends upon :

• Concentration of ions A
• Nature of electrolyte B
• Temperature C
• All of above D

The function of salt bridge is :

• To increase movement onions. A
• To increase the emf of cell. B
• To decrease the temperate C
• To maintain electrical neutrality D

The conductivity of strong electrolyte

• Increases on dilution slightly A
• Does not change on dilution B
• Decreases on dilution C
• Depends on density of electrolyte it self 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

Coinage metals like Au, Pt, Ag and Cu are the least reactive metals and don't liberate H₂gas when treated with acids because

• These have very high positive values of reduction potentials A
• These have very high negative values of reduction potentials B
• Their ionization potentials are lowest C
• Their reduction potentials are close to SHE D

In a Galvanic cell

• Chemical energy is converted into electricity A
• Chemical energy is converted into heat B
• Electrical energy is converted into heat C
• Electrical energy is converted into chemical energy 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

Silver oxide battery has a voltage of

• 2.0 V A
• 1.5 V B
• 2.5 V C
• 1.0 V D

Fe can displace Cu form CuSO4solution because

• Fe is ferromagnetic A
• Fe is below Cu in electrochemical series B
• Fe is above Cu in electrochemical series C
• Fe exists in divalent oxidation state D

Electrochemical series is a list of element S arranged into the increasing order of their

• Standard oxidation potential A
• Standard reduction potential B
• Cell voltage C
• Ionization potential D

The cathodic reaction in the electrolysis of dill H₂SO₄with Pt electrodes

• Reduction A
• Oxidation B
• Both oxidation and reduction C
• neither oxidation or reduction 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

Standard reduction of Zn = -0.76 V and that of Ni is -0.25 V. On coupling them by a salt bridge which of these will act as anode

• Salt bridge will act as anode A
• Zn will act as anode B
• Ni will act as anode C
• None of these D

96500 C of electricity liberates from CuSO₄solution

• 63.5 g of Cu A
• 31.75 g of Cu B
• 96500 g of Cu C
• 100 g of Cu D

• Iodine can oxidise iron A
• Bromine can oxidise iron B
• Iodine can oxidise bromine C
• Iron can oxidise bromine D

Which of the substances Na, Hg, S Pt and graphite can be used as electrodes in electrolytic cells having aqueous solution?

• Na, Pt and graphite A
• Na and Hg B
• Pt and graphite only C
• Na and S only D

• A strong reducing agent A
• A strong oxidising agent B
• Better oxidising agent than hydrogen C
• Less reducing agent than hydrogen D

The unit of specific conductivity is

• Ohm cm^-1 A
• Ohm cm^-2 B
• Ohm^-1cm C
• Ohm^-1cm^-1 D