ECAT Pre Engineering Chemistry Chapter 10 MCQ Test With Answer

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

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

Strong oxidizing agents have

• Greater positive value of standard reduction potential A
• Lesser positive value of standard B
• Greater negative value of standard C
• None of these 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

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

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 of the following is the use of electrolysis?

• Eletrorefining A
• Electroplating B
• Both A and B C
• None of the above D

The galvanic or voltaic cells which are rechargeable called as

• Primary cells A
• Secondary cells B
• Dry cells C
• Infinite cells D

Which one of the following reactions is not spontaneous

• 
  A
• 
  B
• 
  C
• 
  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 reference calomel electrode is made from which of the following?

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

The oxidation number of Mn is KMnO₄is

• +2 A
• +4 B
• +6 C
• +7 D

Coupling of Pb with its Pb⁺⁺/Pb = -0.13 V and Ag with Ag⁺/ Ag = +0.80 V, the cell reaction

• 
  A
• 
  B
• 
  C
• 
  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

• Zn A
• H B
• S C
• O D

The oxidation number of H is -1 in the compound

• H₂O A
• H₃BO₃ B
• NaOH C
• NaH D

In lead accumulator the electrolyte is H₂SO₄solution is

• 30% H₂SO₄ A
• 60% H₂SO₄ B
• 80% H₂SO₄ C
• 90% H₂SO₄ D

A cell in which electric current is produced as a result spontaneous redox reaction is called :

• Dry cell A
• Electrolytic cell B
• Galvanic cell C
• Standard cell D

While balancing an equation by ion electron method, the number of oxygen atoms are balanced by

• OH^- A
• H₂O B
• O₂ C
• H⁺ D

Specific conductivity of a solution

• Increases with dilution A
• Decreases with dilution B
• Remains unchanged with dilution C
• Depends on mass of electrolyte D

The reference electrode is made by using

• ZnCl₂ A
• CuSO₄ B
• HgCl₂ C
• Hg₂Cl₂ 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

Electrolytes in the form of solution or in the fused state have the ability to conduct :

• Light. A
• Electricity. B
• Ions. C
• Electrons. 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

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

Which of the following cannot conduct electricity :

• NaCl fused. A
• NaCl(aq)
  B
• NaCl(Solid)
  C
• Both (b) and (c) D

In a compound an atom has negative oxidation state because

• Atom is negatively charged A
• Atom acts as cathode B
• Atom is more electronegative C
• Atom has lowest ionization energy D

In electronic watches or electronic calculators the tiny batteries used are

• Alkaline battery A
• NICAD battery B
• Fuel cell C
• Silver oxide battery D

When electricity is passed through molten electrolyte consisting of alumina and cryolite, 13.5 g of Al are deposited. The number of faradays of electricity passed must be

• 2.0 A
• 1.5 B
• 1.0 C
• 0.5 D