At 298 K the molar conductivities at infinite dilution () of NH4Cl, KOH and KCl are 152.8, 272.6 and 149.8 S cm2 mol-1respectively. The of NH4OH in Scm2 mol-1 and % dissociation of 0.01 M NH4OH with = 25.1 S cm2 mol-1 at the same temperature are
275.6, 0.91
275.6, 91
266.6, 96
30, 84
The products obtained at the cathode and anode respectively during the electrolysis of aqueous K2SO4 solution using platinum electrodes are
O2, H2
H2, O2
H2, SO2
K2, SO2
Same amount of electricity is passed through aqueous solutions of AgNO3 and CuSO4. The number of Ag and Cu atoms deposited are x and y respectively. The correct relationship between x and y is
x <y
x= 2y
x = y
y = 2x
B.
x= 2y
When same amount of electncty is passed through AgNO3 and CuSO4 aqueous solutions. The relations between Ag+ and Cu2+ ion is as follows
1 mol of Ag+ = 1/2 mol of Cu2+
(Cu2+ required 1 mol of electron for each moles of Cu2+ ion)
Thus for,
x- mol of Ag+ , we get y/2 moles of Cu2+ ions. Hence, x = 2y.
In the acidic solution of copper sulphate and alkaline solution of copper cyanide respectively same electric current is flown for a definite time, which of the following statement is correct for this?
Amount of copper deposited in both the solution is the same
Amount of copper deposited in alkaline copper cyanide solution is less
Amount of copper deposited in acidic copper sulphate solution is less
None of the above
What is the emf of the cell, whose half cells are given below
Mg2+ + 2e- → Mg(s) E =-2.37 V
Cu2+ + 2e- → Cu(s) E =+0.34 V
-2.30V
1.336V
2.17V
2.93V
Zn | | Cu
If the standard reduction potential of zinc electrode and copper half cell is -0.76 V and 0.34 V respectively then the emf will be
1.1 V
1.4 V
1.34 V
None of these
Rusting on iron needs
dry air
air and water
distilled water and carbon dioxide
oxygen and carbon dioxide
In galvanic cell, the salt bridge is used to
complete the circuit
reduce the electric resistance in the cell
separate cathode from anode
carry salts for the chemical reaction
A cell, with cell constant 0.4 cm-1, has the resistance of 40 ohm of a 0.01 M solution of an electrolyte, then the molar conductivity in ohm-1 cm2 mol-1 will be
104
103
102
1
If the standard elelctrode potential for the cell Zn | Zn2+ (aq) || Cu2+ (aq) | Cu is 1.10 V, then the maximum work done by this cell will be
-106.15 kJ
-212.30 kJ
-318.45 kJ
-424.60 kJ