ECAT Pre Engineering Chemistry Chapter 10 MCQ Test With Answer

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

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

The cell in which a non-spontaneous redox reaction takes place as a result electricity is known as :

• Electrolytic cell. A
• Voltaic cell. B
• Daniel cell. C
• Dry cell. 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

In a solution of CuSO₄how much time will be required to precipitate 2g copper by 0.5 ampere current?

• 12157.48 sec A
• 102 sec B
• 510 sec C
• 642 sec 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

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

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

What will be the weight of deposited silver on passing 965 coulombs of electricity in solution of AgNO₃?

• 1.08 g A
• 2.16 g B
• 0.54 g C
• 0.27 g D

Reduction or oxidation potential of standard hydrogen electrode is :

• 0.0 Volt A
• 0.8Volt B
• 1.0Volt C
• 1.8Volt 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

F₂, Cl₂, Br₂and l₂lie below SHE is the Electro chemical series that is why these

• Undergo reduction A
• Undergo oxidation B
• Liberate H₂gas with steam C
• None of these D

• Zn A
• H B
• S C
• O D

Caustic soda is obtained by electrolysis of conc. aqueous solution of NaCI in a cell called

• Daniell's cell A
• Nelson's cell B
• Down's cell C
• Voltaic cell D

Lead accumulator stops discharging current when

• Lead at anode converted to PbO₂ A
• PbO₂at cathode converted to Pb B
• Both electrodes are completely covered with PbSO₄ C
• Both electrodes are completely covered with Pb(OH)₂ D

Which of the following correctly describes the process occurring at the electrodes when molten NaCl is electrolyzed:

• No reaction at anode, reduction at cathode. A
• No reaction at cathode, oxidation at anode. B
• Oxidation at anodes, reduction at cathode. C
• Oxidation at cathode, reduction at anode. D

In the reaction K₂Cr₂O₇+ HCl + CrCl₃+ Cl₂+ H₂O the element which is reduced is

• K A
• Cl B
• Cr C
• H D

A dry alkaline cell has porous Zn anode and MnO₂as cathode the electrolyte used is

• Ca(OH)₂ A
• NaOH B
• KOH C
• NH₄OH D

If a salt bridge is removed between the two half cells, the voltage

• Drops to zero A
• Does not change B
• Increases gradually C
• Increases rapidly D

Which of the following is a strong electrolyte?

• Ca(NO₃)₂ A
• HCN B
• CH₃COOH C
• NH₄OH D

Sodium can be obtained by :

• Electrolysis of acidified water. A
• By heating NaCl and water at 100°
  B
• Electrolysis of molten sodium chloride. C
• Electrolysis of aqueous sodium chloride. 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

The substance having highest conductivity at room temperature among the following is

• 0.1 N HCl A
• 0.1 N NaCl
  B
• Graphite C
• Glass D

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

Reaction takes place at anode is

• Ionization A
• Reduction B
• Oxidation C
• Hydrolysis 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

An electric current is passed through silver voltameter connected to a water voltmeter. The cathode of the silver voltameter is 0.108 g more at the end of the electrolysis. The volume of oxygen evolved at STP is

• 56 cm³ A
• 550 cm³ B
• 5.6 cm³ C
• 11.2 cm³ D

If the standard electrode potential of CU²⁺/Cu electrode is 0.34 V, what is the electrode potential of 0.01 M concentration of Cu²⁺? (T=298)

• 0.399 V A
• 0.281 V B
• 0.222 V C
• 0.176 V D

In a hydrogen-oxygen fuel cell, combustion of hydrogen occurs to

• Generate heat A
• Remove adsorbed oxygen from electrode surfaces B
• Produce High purity water C
• Create potential difference between two electrodes D

The unit of specific conductivity is

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