ECAT Pre Engineering Chemistry Chapter 10 MCQ Test With Answer

A current of 9.65 ampere flowing for 10 minutes deposits 3.0 g of the metal which is monovalent. The atomic mass of the metal is

• 10 A
• 50 B
• 30 C
• 96.5 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

Which statement is correct for the fuel cells

• These cells operate at low temperature A
• These cells operate at low temperature B
• No catalyst used for the formation of water C
• MnO₂is used as electrolyte D

In passage of electricity through aqueous solution of AgNO₃silver dissolves at anode to form Ag⁺, the electrodes are

• Silver metal A
• Pt metal B
• Graphite C
• Copper metal D

Metals like Fe, Mg, Al, Cr, Zn have more negative reduction potentials that is whey

• These don't react with steam A
• These react very slowly with steam to liberate H₂gas B
• These react rapidly with steam to produce the metallic oxides and liberate H₂gas C
• These react with cold water violently 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

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

During electrolysis of KNO₃, H₂is evolved

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

The reference calomel electrode is made from which of the following?

• ZnCl₂ A
• CuSO₄ B
• Hg₂Cl₂ C
• HgCl₂ D

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

• H₂gas A
• Cl₂gas B
• NaOH C
• No metal 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 oxidation number of H is -1 in the compound

• H₂O A
• H₃BO₃ B
• NaOH C
• NaH 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

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

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

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

In a Galvanic cell, the electrons flow from

• A node to cathode through the solution A
• Cathode to anode through the external circuit B
• Cathode to anode through the external circuit C
• Anode to cathode through the external circuit D

What are the products electrolysis of aqueous sodium chloride at two electrodes

• Chlorine at anode and oxygen at cathode. A
• Hydrogen at anode and chlorine at cathode. B
• Chlorine at anode and hydrogen at cathode. C
• Chlorine at anode and sodium at cathode. D

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

Time required to deposit one millimole of aluminium metal by the passage of 9.65 amperes through molten electrolyte containing aluminium ion is

• 30 s A
• 10 s B
• 30,000 s C
• 10,000 s 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

Cell potential depends upon :

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

When fused PbBr₂is electrolyed then

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

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

• One A
• Zero B
• Different C
• Same 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

An electrochemical cell is based upon

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

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

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

Which of the following will be good conductor of electricity

• Pure distilled water A
• Molten NaCl B
• Dilute solution of glucose C
• Chloroform 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