Na is used in reduction of Zn salt because
E°Zn (oxi) > E°Na (oxi)
E°Zn (red) > E°Na (red)
E°Zn (oxi) < E°Na (oxi)
both (a) and (b)
Reduction potentials of A, B, C and D are 0.8 V, 0.79 V, 0.34 V and -2.37 V respectively. Which element displaces all the other three elements?
B
A
D
C
C.
D
The element having lower reduction potential can displace metal having higher reduction potential. Among the given options, D has the least reduction potential. Therefore, it can displace all other metals.
During the electrolytic reduction of alumina, the reaction at cathode is
2H2O → O2 + 4H+ + 4e-
3F- → 3F + 3e-
Al3+ + 3e- → Al
2H+ + 2e- → H2
One ampere of current is passed for 9650 seconds through molten AlCl3. What is the weight in grams of Al deposited at cathode? (atomic weight of Al = 27)
0.9
9.0
0.09
90.0
Molten CuCl2 is electrolysed using platinum electrodes. The reaction occurring at anode is
2Cl- → Cl2 (g) + 2e-
Cl2(g) + 2e- → 2Cl
Cu2+ + 2e- → Cu (s)
Cu(s) → Cu2+ + 2e-
During the electrolysis of cryolite, aluminium and fluorine are formed in ...... molar ratio :
1:2
2:3
1:1
1:3
What is the reduction electrode potential (in volts) of copper electrode when [Cu2+] = 0.01 M is in a solution at 25°C?
(E° of Cu2+/ Cu electrode is + 0.34 V)
0.3991
0.2809
0.3105
0.3695
The product obtained at anode when 50% H2SO4 aqueous solution is electrolysed using platinum electrodes is :
H2SO3
H2S2O8
O2
H2
0.066 g of metal was deposited when a current of 2 ampere is passed through a metal ion solution for 100 seconds. What is the electrochemical equivalent (in gram coulomb-1) of the metal ?
3.3 × 10-6
3.3 × 10-4
0.033
3.3
When X amperes of current is passed through molten AlCl3 for 96.5 s, 0.09g of aluminium is deposited. What is the value of X?
10 ampere
20 ampere
30 ampere
40 ampere