CBSE
Multiple Choice QuestionsIf the Zn2+/Zn electrode is diluted to 100 times then the change in emf :
increase of 59 mV
decrease of 59 mV
increase of 29.5 mV
decrease of 29.5 mV
Ni/Ni2+ [1.0 M] || Au3+ [1.0 M]/Au (where E° for Ni2+/Ni is -0.25 V E° for Au3+/Au is 0.150 V)
Whar is the emf of the cell ?
+ 0.4 V
- 1.75 V
+ 1.25 V
+ 1.75 V
The specific conductance of a N/ 10 KCl at 25°C is 0.0112 ohm-1cm-1.The resistance of cell containing solution at the same temperature was found to be 55 ohm. The cell constant will be
6.16 cm-1
0.616 cm-1
0.0616 cm-1
616 cm-1
The time period to coat a metal surface of 80 cm2 with 5 x 10-3 cm thick layer of silver (density 1.05 g cm-3) with the passage of 3 A current through a silver nitrate solution is
115 sec
125 sec
135 sec
145 sec
For the following concentration cell, to be spontaneous Pt(H2)P1 atm. |HCl | Pt(H2)P2 atm. Which of the following is correct?
P1=P2
P1<P2
P1>P2
Can't be predicted
If equivalent conductance of 1 M benzoic acid is 12.8 ohm-1 cm and if the conductance of benzoate ion and H+ ion are 42 and 288 .42 ohm-1 cm2 respectively .Its degree of dissociation is :
39 %
3.9 %
0.35 %
0.039 %
In acidic medium MnO42- is converted to Mn2+ .The quantity of electricity in faraday required to reduce 0.5 mole of MnO42- to Mn2+ would be :
2.5
1
5
0.5
If hydrogen electrode dipped in two-solution of pH = 3 and pH = 6 and salt bridge is connected , the emf of resulting cell is :
0.177 V
0.3 V
0.052 V
0.104 V
During electrolysis of water the volume of oxygen liberated is 2.24 dm3 .The volume of hydrogen liberated , under same conditions will be :
2.24 dm3
1.12 dm3
4.48 dm3
0.56 dm3
In a lead storage battery , reaction at cathode is :
Pb + SO42- PbSO4 + 2e-
Pb + PbO2 + 2H2SO4 2PbSO4 + 2H2O
PbSO4 + 2e- Pb + SO42-
PbO2 + 4H+ + SO42- + 2e- PbSO4 + 2H2O
