Tag: electrochemistry

Quizzes (9) Questions (132)

Questions Related to electrochemistry

Multiple choice metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

A compass placed in an electric field will be deflected due to:

  1. heating effect of current

  2. magnetic effect of current

  3. conducting effect

  4. resistance of the needle to the electric field
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

An electric current causes a magnetic field around it just like a magnet causes a magnetic field. When you moved the compass near an electric field, the magnetic field produced due to the electric field deflects the compass.


Hence, the correct option is $\text{B}$

Multiple choice metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

Which of the following is a good conductor of electricity?

  1. Tap water

  2. Distilled water

  3. Sea water

  4. Rain water
Reveal answer Fill a bubble to check yourself
A,C,D Correct answer
Explanation
Sea water, tap water, and rainwater comprise of salt and many other impurities whereas distilled is void of such impurities. 

Those impurities, act as ions and help in the transfer of charge.
 
Hence, they are good conductor of electricity.

Distilled water is highly purified water that does not contain any salts. Hence, it do not conduct electricity.

Therefore, option A, C and D are correct.

Multiple choice metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

Which of the following does not conduct electricity ?

  1. Molten NaoH

  2. Molten KOH

  3. Solid NaCI

  4. Aqueous NaCI
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Solid NaCl consists of ions held together in a rigid crystal lattice; because these ions are not free to move, the solid cannot conduct electricity. Molten and aqueous forms allow ions to move freely, enabling conduction.

Multiple choice metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

An acidic solution of Cu+ salt containing 0.4 g of Cu+ is electrolysed until all the Cu is deposited. The electrolysis is continued for 7 more minutes with volume of the solution kept at 100 ml and the current at 1.2 amp. Calculate volume of the gases evolved at NTP during entire electrolysis( atomic weight of Cu= 63.6)

  1. H2 = 68.32 ; O2 = 85.23 ml

  2. H2 = 40.34 ; O2 =70.12 ml

  3. H2= 51.46 ; O2 = 90.12 ml

  4. H2=58.46 ; O2 = 99.68 ml
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

This is a complex stoichiometry and electrolysis problem. After Cu+ is deposited, the electrolysis of water occurs (2H2O -> 2H2 + O2). Calculating moles of electrons from current and time, then applying Faraday's laws, leads to the volumes of H2 and O2 evolved.

Multiple choice metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

An electrolytic cell was set up. Distilled water is placed in the cell and battery is switched on. The bulb is also connected through a battery. The bulb will:

  1. glow

  2. not glow

  3. partially glow

  4. none of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Distilled water is a bad conductor of electricity. It do not contains any impurities to carry the current. So the circuit will not be completed for the bulb to glow.

Multiple choice metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

Given below are the half cell reactions

${ Mn }^{ 2+ }+{ 2e }^{ - }\longrightarrow { Mn }  E=-1.81V$

$2\left( { Mn }^{ 3+ }+{ e }^{ - }\longrightarrow { Mn }^{ 2+ } \right) E=+1.51V$ will be

        




  1. 0.33V ; the reaction will not occur .

  2. 0.33V ; the reaction will occur.

  3. 2.69V ; the reaction will not occur.

  4. 2.69V ; the reaction will occur
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

To find the cell potential, we combine the half-reactions. The overall reaction is 3Mn^2+ -> Mn + 2Mn^3+. The E_cell = E_cathode - E_anode. Using the given values, E_cell = 1.51 - 1.81 = -0.30V. Since E is negative, the reaction is non-spontaneous.

Multiple choice metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

The first step in the extraction of Cu from copper pyrites is?

  1. Reduction by carbon

  2. Electrolysis of ore
  3. A Roasting of ore in $O _2$

  4. Magnetic separation
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Copper pyrites (CuFeS2) contain iron and copper sulfides. The initial step in extracting copper from copper pyrites is roasting the ore in the presence of oxygen to remove excess sulfur as sulfur dioxide and convert iron sulfide into iron oxide.