ECAT Pre Engineering Chemistry Chapter 10 MCQ Test With Answer

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

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

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

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

In electrolytic cells, the chemical changes may be :

• Either spontaneous or non-spontaneous A
• Always spontaneous B
• Always non-spontaneous C
• More spontaneous and less non-spontaneous. 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

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

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

When electric current is used to carry out non-spontaneous redox, the process is called

• Hydrolysis A
• Electrolysis B
• Decomposition C
• Neutralization D

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

• K A
• Cl B
• Cr C
• H D

Silver oxide battery has a voltage of

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

Reaction takes place at anode is

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

In the presence of copper electrodes the electrolysis of aqueous CuSO₄produces at cathode

• H₂gas A
• O₂gas B
• SO₂gas C
• Cu metal 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

The reference electrode is made by using

• ZnCl₂ A
• CuSO₄ B
• HgCl₂ C
• Hg₂Cl₂ 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

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

Prevention of corrosion of iron by Zn coating is called

• Galvanization A
• Cathodic protection B
• Electrolysis C
• Photoelectrolysis 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

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

By using graphite electrode the electrolysis of aqueous solution of NaCI produces at anode

• H₂gas A
• Cl₂gas B
• NaOH C
• No metal D

The oxidation number of free element is always taken to be

• 0 A
• 1 B
• 2 C
• -1 D

Out of Cu, Ag, Fe and Zn the metal which can displace all others from theri salt solution is

• Ag A
• Cu B
• Zn C
• Fe 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

Which of the following (1 M) conducts more electricity?

• Sulphuric acid A
• Boric acid B
• Nitric acid C
• Phosphorus acid 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

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

• BaCl₂ A
• KCl B
• NaCl C
• MgCl₂ D

Calculate the amount of charge flowing in 2 minute in a wire of resistance 10Ωwhen a potential difference of 20 V is applied

• 120 C A
• 240 C B
• 20 C C
• 4 C D

The two half cells of a galvanic cell are connected by

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