﻿  For the cell Zn/Zn2+ (aq) || Cu2+(aq) | Cu, derive the relation between E°cell and Kc at 298 k. from Chemistry Electrochemistry Class 12 Nagaland Board

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For the cell Zn/Zn2+ (aq) || Cu2+(aq) | Cu, derive the relation between E°cell and Kc at 298 k.

Gibbs energy of the reaction given by:
${∆}_{r}G$ = – nFE(cell)
thus the reaction
Zn(s) + Cu2+(aq)---> Zn2+(aq) + Cu(s)

${∆}_{r}G$ = – 2FE(cell)

but when we write the reaction
2 Zn (s) + 2 Cu2+----->2 Zn2+(aq) + 2Cu(s)

${∆}_{r}G$ = – 4FE(cell)

If the concentration of all the reacting species is unity, then
E(cell)${\mathrm{E}}_{\mathrm{cell}}^{0}$
and we have
${∆}_{r}G$ = – nF${\mathrm{E}}_{\mathrm{cell}}^{0}$

Thus, from the measurement of ${\mathrm{E}}_{\mathrm{cell}}^{0}$ we can obtain an important thermodynamic quantity, ${∆}_{r}G$, standard Gibbs energy of the reaction.
From the latter we can calculate equilibrium constant by the equation:

${∆}_{r}G$ = –RT ln Kc

198 Views

Can you store copper sulphate solutions in a Zinc pot?

No. Because zinc is more reactive than copper and thus holes will be developed in zinc pot.

Cu2+(aq) + Zn(s) → Zn2+ (aq) + Cu(s)
1384 Views

Calculate the emf of the cell in which the following reaction takes place:
Ni(s) + 2Ag+ (0.002 M) $\to$ Ni2+ (0.160 M) + 2Ag(s)
Given that

$\mathrm{Ni}\left(\mathrm{s}\right)+2{\mathrm{Ag}}^{+}\left(\mathrm{aq}\right)\to {\mathrm{Ni}}^{2+}\left(\mathrm{aq}\right)+2\mathrm{As}\left(\mathrm{s}\right)$

or

The equation is also written as

or

= 1.05 V – 0.0295 x log 80

= 1.05 V – 0.0295 x 1.9031

= 1.05 V – 0.056 = 0.99 V.

1585 Views

How would you determine the standard electrode potential of the system Mg2+/Mg?

Use standard hydrogen electrode as anode and Mg2+ | Mg as a cathode we can measure the standard electrodepotential of systemMg2+ | Mg. Standard hydrogen electrode, represented by Pt(s), H2(g) (1 atm) | H+ (aq) and dip the electrode of Magnesium wire in a 1M MgSO4 solution .The standard hydrogen electrode is always zero.
Use formula
Eocell = Eo right  – Eoleft
The standard hydrogen electrode is always zero.
So that the value of
Eoleft =0
Hence
Eocell = Eo Mg|Mg2+
Or
Eo Mg|Mg2+= Eocell
2203 Views

Calculate the potential of hydrogen electrode in contact with a solution whose pH is 10.

For hydrogen electrode, ,
given that      pH = 10
use formula [H+] = 10–pH
so that  [H+] = 10−10 M
Electrode reaction will
H+  + e –  →1/2 H2
Use the formula

1279 Views

Consult the table of standard electrode potentials and suggest three substance that can oxidize ferrous ions under suitable conditions.