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
C.
P1>P2
Pt (H2) P1 atm. |HCl|Pt(H2) P2 atm. For spontaneous reaction, Ecell should be positive so P1> P2
Also, if P1 > P2 oxidation occurs at L.H.S. electrode
and reduction occurs at R.H.S. electrode.
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.