ECAT Pre Engineering Chemistry Chapter 10 MCQ Test With Answer

During electrolysis of KNO₃, H₂is evolved

• Anode A
• Cathode B
• Both a and b C
• None 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

Which statement is incorrect for balancing of redox reactions by ion-electron method

• The reaction is splitted into two half reactions A
• H₂O and H⁺ions are added for acidic or neutral reaction to balance O and H atoms B
• To balance H, HCi, is added C
• To balance O and H in the alkaline reaction OH^-added D

When aqueous NaCl is electrolyzed, which of the following ions get discharged at anode :

• H⁺

  A

• Na⁺

  B

• OH^-

  C

• Cl^-

  D

When electrically is passed through molten Al₂O₃+ Na₃AlF₆and 13.5 gms of Al are deposited, the number of farady must be

• 0.5 A
• 1.0 B
• 1.5 C
• 2.0 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

A smuggler could not carry gold by chemically depositing iron on the gold surface since

• Gold is denser A
• Iron rusts B
• Gold has higher reduction potential then iron C
• Gold has lower reduction potential then iron 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

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

The oxidation number of H is -1 in the compound

• H₂O A
• H₃BO₃ B
• NaOH C
• NaH D

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

The oxidation number of free element is always taken to be

• 0 A
• 1 B
• 2 C
• -1 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

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

In KO₂the oxidation state of oxygen is

• -2 A
• -1 B
• +1/2 C
• -1/2 D

During electrolysis, the reaction that takes place at cathode is :

• Reduction A
• Both (a) and (c) B
• Oxidation C
• No reaction occurs D

Alkaline battery has a voltage of

• 4.5 V A
• 3.5 V B
• 2.5 V C
• 1.5 V D

The oxidation number of chromium in K₂Cr₂O₇is

• 14 A
• 12 B
• 6 C
• None of these D

Sodium metal is obtained by the electrolysis of fused NaCl in cell is called

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

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

• K A
• Cl B
• Cr C
• H D

Reaction takes place at anode is

• Ionization A
• Reduction B
• Oxidation C
• Hydrolysis D

The electrode through which the electrons enter the electrolytic solution is electrolytic solution is

• Anode A
• Cathode B
• May be anode or cathode C
• None of these D

Matals usually conduct electricity because

• There are mobile electrons in the metallic structure A
• Metals are decomposed by current B
• Metals have high resistance C
• In metals the ions are free to move 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

Metallic conduction is also called as :

• Ionic conduction. A
• Protonic conduction. B
• Electronic conduction C
• Super conduction D

A cell in which spontaneous redox reaction generates an electric current is called

• Electrolytic cell A
• Electrochemical cell B
• Voltaic or Galvanic cell C
• Biological cell D

Which statement is incorrect about standard hydrogen electrode

• Its oxidation and reduction potential is zero A
• It consists of Pt wire dipped on 1 molar HCI solution B
• The electrolyte is 1 molar NaOH solution C
• H₂gas is passes in it at 1 atmospheric pressure D

The value of SHE is cathode and anode is always taken to be

• One A
• Zero B
• Different C
• Same D

Which of the following is a strong electrolyte?

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