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
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
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
If 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
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 %
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
The standard oxidation potential E° for the half cell reaction are
- 0.35 V
+ 0.35 V
0.17V
1.17V.
To observe the effect of concentration on the conductivity of electrolytes of different nature were taken in two vessels A and B. A contains weak electrolyte NH4OH and B contains strong electrolyte NaCl. In both containers, concentration of respective electrolyte was increased and conductivity observed
in A conductivity increases, in B conductivity decreases
in A conductivity decreases, while in B conductivity increases
in both A and B conductivity increase
in both A and B conductivity decreases.
D.
in both A and B conductivity decreases.
Solution which contains large number of ions compared to another solution of same concentration at the same temperature has more conductance and is said to be stronger electrolyte. The one which has relatively small number of ions is called weak electrolyte. If concentration of respective electrolyte was increased, the equivalent conductance decreased in each case, but rapid decrease in equivalent conductance is seen in weak
electrolyte.