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Question
Answer the following in one or two sentences.
Write Nernst equation. What part of it represents the correction factor for nonstandard state conditions?
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Solution
1) For any general reaction, aA + bB → cC + dD
Nernst equation is given by
`"E"_"cell" = "E"_"cell"^circ - "RT"/"nF" "ln" (["C"]^"c" ["D"]^"d")/(["A"]^"a" ["B"]^"b")` OR
`"E"_"cell" = "E"_"cell"^circ - (2.303 "RT")/"nF" log_10 (["C"]^"c" ["D"]^"d")/(["A"]^"a" ["B"]^"b")`
where n = moles of electrons used in the reaction, F = Faraday = 96500 C,
T = temperature in kelvin,
R = gas constant = 8.314 J K-1 mol-1
2) The second term in the Nernst equation is the correction for nonstandard state conditions.
Correction factor is `(2.303 "RT")/"nF" log_10 (["C"]^"c" ["D"]^"d")/(["A"]^"a" ["B"]^"b")`
RELATED QUESTIONS
Consider the half reactions with standard potentials.
- \[\ce{Ag^{\oplus}_{ (aq)} + e^{\ominus} -> Ag_{(s)}E^\circ = 0.8 V}\]
- \[\ce{I2_{(s)} + 2e^\ominus -> 2I^{\ominus}_{(aq)} E^\circ = 0.53V}\]
- \[\ce{Pb^{2\oplus}_{(aq)} + 2e^{\ominus} -> Pb_{(s)} E^\circ = -0.13 V}\]
- \[\ce{Fe^{2\oplus} + 2e^{\ominus} -> Fe_{(s)} E^\circ = -0.44 V}\]
The strongest oxidising and reducing agents respectively are ______.
Answer the following in one or two sentences.
What is standard cell potential for the reaction
\[\ce{3Ni_{(s)} + 2Al^{3+} (1M) → 3Ni^{2+} (1M) + 2Al(s)}\], if `E_"Ni"^circ` = –0.25 V and `"E"_("Al")^circ` = –1.66 V?
Answer the following:
Calculate emf of the cell:
Zn(s) |Zn2+ (0.2 M)||H+ (1.6 M)| H2(g, 1.8 atm)| Pt at 25 °C.
Calculate emf of the cell at 25°C.
Zn(s) | Zn2+ (0.08 M) || Cr3+ (0.1 M) | Cr(s)
`E_(Zn)^0` = −0.76 V, `E_(Cr)^0` = −0.74 V
Answer the following:
Predict whether the following reaction would occur spontaneously under standard state condition.
`"Ca"_(("s")) + "Cd"_(("aq"))^(2+) -> "Ca"_(("aq"))^(2+) + "Cd"_(("s"))`
What is cell voltage?
Calculate the voltage of the cell Sn(s) / Sn2+(0.02 M) // Ag+ (0.01 M) / Ag(s) at 25 °C.
Given: `"E"_"Sn"^circ` = - 0.136, `"E"_"Ag"^circ` = 0.800 V
Standard reduction electrode potentials of three metals A, B and C are +0.5 V, −3.0 V and −1.2 V respectively. The reducing power of these metals is ______.
Nernst equation for the following cell reaction at 298 K is:
\[\ce{Mg_{(s)} | Mg^{2+}_{( aq)} || Ag^+_{( aq)} | Ag_{(s)}}\]
Identify the strongest reducing agent from the data given below:
| Element | `"E"^0 ("V")` |
| Al | −1.66 |
| Fe | −0.44 |
| Hg | +0.79 |
| Cu | +0.337 |
What is the standard emf of the following cell?
\[\ce{Ni_{(s)} | Ni^{2+}_{( aq)} || Au^{3+}_{( aq)} | Au_{(s)}}\]
if \[\ce{E^0_{Ni}}\] = −0.25 V, \[\ce{E^0_{Au}}\] = 1.50 V.
What is the ΔG0 for the following reaction?
\[\ce{Al_{(s)} + Fe^{3+}_{( aq)} -> Al^{3+}_{( aq)} + Fe_{(s)}}\]; \[\ce{E^0_{cell}}\] = +2.43
For the following cell, standard potential of copper electrode is 0.337 V and standard cell potential is 0.463 V.
\[\ce{Cu | Cu^{2+} (1 M) || Ag^+ (1 M) Ag}\]
What is the standard potential of silver electrode?
What is the standard potential of cell, Ni | Ni2+ (1M) || Cu2+ (1 M) | Cu?
If E°Cu = 0.337 V and E°Ni = - 0.236 V.
The standard electrode potential of Zn and Ni are - 0.76 V and - 0.25 V respectively. If the reaction takes place in the cell constructed between these two electrodes is spontaneous. What is the standard emf of the cell?
The standard EMF for the cell reaction,
\[\ce{Zn + Cu^{2+} -> Zn^{2+} + Cu}\],
is 1.10 V at 25°C. The EMF of the cell reaction, when 0.1 M Cu2+ and 0.1 M Zn2+ solutions are used at 25°C is:
Construct a cell from Ni2+ | Ni and Cu2+ | Cu Cu half cells. Write the cell reaction and calculate `E_("cell")^0`
`(E_("Ni")^0 = - 0.236 V and E_("Cu")^0 = + 0.337 V)`
Define standard electrode potential.
The standard potential of the electrode Zn2+(0.02M) |Zn(s) is − 0.76 V. Calculate the electrode potential of the zinc electrode.
Calculate the emf of the following cell at 25°C.
Zn(s)|Zn2+(0.08 M) || Cu2+(0.l M) |Cu(s)
E0zn = − 0.76 V, E0cu = 0.36 V.
Write net cell reaction.
Write the value of `(2.303 RT)/F` in the Nernst equation?
