Advertisements
Advertisements
प्रश्न
Describe the electrolysis of molten NaCl using inert electrodes.
Advertisements
उत्तर
1. The electrolytic cell consists of two iron electrodes dipped in molten sodium chloride and they are connected to an external DC power supply via a key.
2. The electrode which is attached to the negative end of the power supply is called the cathode and the one is which attached to the positive end is called the anode.
3. Once the key is closed, the external DC power supply drives the electrons to the cathode and at the same time pulls the electrons from the anode.
Cell reactions:
Na+ ions are attracted towards the cathode, where they combine with the electrons and are reduced to liquid sodium.
Cathode (reduction)
\[\ce{Na^+_{ (l)} + e^- -> Na_{(l)}}\]
E0 = – 2.71 V
Similarly, Cl– ions are attracted towards anode where they losses their electrons and oxidised to chlorine gas.
Anode (oxidation)
\[\ce{2Cl^-_{ (l)} -> Cl2_{(g)} + 2e^-}\]
E0 = – 1.36 V
The overall reaction is,
\[\ce{2Na^+_{ (l)} + 2Cl^-_{ (l)} -> 2Na_{(l)} + Cl2_{(g)}}\]
E0 = 4.07 V
Electrolysis of molten NaCl
The negative E0 value shows that the above reaction is a non spontaneous one. Hence, we have to supply a voltage greater than 4.07 V to cause the electrolysis of molten NaCl.
In an electrolytic cell, oxidation occurs at the anode and reduction occurs at the cathode as in a galvanic cell, but the sign of the electrodes is the reverse i.e., in the electrolytic cell cathode is −ve and the anode is +ve.
APPEARS IN
संबंधित प्रश्न
Among Zn and Cu, which would occur more readily in nature as metal and which as an ion?
E°cell for the given redox reaction is 2.71 V
Mg(s) + Cu2+ (0.01 M) → Mg2+ (0.001 M) + Cu(s)
Calculate Ecell for the reaction. Write the direction of flow of current when an external opposite potential applied is
(i) less than 2.71 V and
(ii) greater than 2.71 V
Zinc can be coated on iron to produce galvanized iron but the reverse is not possible. It is because ____________.
A gas X at 1 atm is bubbled through a solution containing a mixture of 1 MY− and 1 MZ− at 25°C. If the reduction potential of Z > Y > X, then ______.
A copper electrode is dipped in 0.1 M copper sulphate solution at 25°C. Calculate the electrode potential of copper.
[Given: \[\ce{E^0_{{Cu^{2+}|Cu}}}\] = 0.34 V]
`E_(cell)^Θ` for some half cell reactions are given below. On the basis of these mark the correct answer.
(a) \[\ce{H^{+} (aq) + e^{-} -> 1/2 H_2 (g); E^Θ_{cell} = 0.00V}\]
(b) \[\ce{2H2O (1) -> O2 (g) + 4H^{+} (aq) + 4e^{-}; E^Θ_{cell} = 1.23V}\]
(c) \[\ce{2SO^{2-}_{4} (aq) -> S2O^{2-}_{8} (aq) + 2e^{-}; E^Θ_{cell} = 1.96V}\]
(i) In dilute sulphuric acid solution, hydrogen will be reduced at cathode.
(ii) In concentrated sulphuric acid solution, water will be oxidised at anode.
(iii) In dilute sulphuric acid solution, water will be oxidised at anode.
(iv) In dilute sulphuric acid solution, \[\ce{SO4^{2-}}\] ion will be oxidised to tetrathionate ion at anode.
A galvanic cell has electrical potential of 1.1V. If an opposing potential of 1.1V is applied to this cell, what will happen to the cell reaction and current flowing through the cell?
Standard reduction electrode potentials of three metals A, B and C are respectively + 0.5 V, – 3.0 V. and – 1.2 V. The reducing powers of there metal is.
On which electrode the oxidation reaction takes place?
Which of the following is incorrect?
