ELECTROCHEMISTRY QUIZ-1

Q1. What is the potential of the cell containing two hydrogen electrodes as represented ahead,

•  - 0.295 V
•  - 0.0591
•  0.0591 V
•  0.295 V

Solution

Q2.Which gains electrons more easily?

•  Mg^(2+)
•  H^+
•  Na^+
•  K^+

Solution
E_RP^° for H is maximum in these

Q3.  The number of faraday required to generate 1 g-atom of Mg from MgCl_2 is :

•   4
•  3
•  1
•  2

Solution
1 g atom of Mg = 2g eq. Mg = 2 faraday.

Q4. The increase in equivalent conductivity of an strong electrolytic solution with dilution is attributed to :

•  Increase in number of ions per unit volume
•  Increase in molecular attraction
•  Increase in degree of dissociation
•  Increase in ionic mobility

Solution
Ionic mobilities increase on dilution.

Q5.If Mg^(2+)+2e ⟶Mg(s); E= -2.37 V, Cu^(2+) +2e ⟶Cu(s); E= + 0.34 V? The e.m.f. of the cell Mg | Mg^(2+) ||Cu^(2+) |Cu is∶

•  2.71 V
•  2.30 V
•  2.80 V
•  1.46 V

Solution
 

Q6. In the electrolysis of which solution, OH^- ions are discharged in preference to Cl^- ions?

•  Dilute NaCl
•  Very dilute NaCl
• Fused NaCl
•  Solid NaCl

Solution

Q7.Which will reduce zinc oxide to zinc?

•  Fe
•  Cu
•  Mg
•  Pb

Solution
Magnesium is more electropositive than zinc, hence it can reduce Zn^(2+) (magnesium is placed above zinc in electrochemical series). Mg + ZnO → MgO + Zn

Q8.What flows in the internal circuit of Agalvanic cell?

•  Electrons
•  Ions
•  Electricity
•  Atoms

Solution
In the internal circuit of Agalvanic cell ions flow while in the external circuit, there is Aflow of electrons from zinc rod to copper rod.

Q9.When electric current is passed through a cell having an electrolyte, the positive ions move towards the cathode and the negative ions towards the anode. If the cathode is pulled out of the solution :

•  The positive and the negative ions both will move towards the anode
•  The positive ions will start moving towards the anode; the negative ions will stop moving
•  The negative ions will continue to move towards the anode; the positive ions will stop moving
•  The positive ions and the negative ions will start moving randomly

Solution
There will be no passage of current and ions will show simply diffusion

Q10. A metal having negative reduction potential when dipped in the solution of its own ions, has a tendency :

•  To be deposited from the solution
•  To pass into the solution
•  To become electrically positive
• To become electrically positive

Solution