Advertisements
Advertisements
प्रश्न
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.
Advertisements
उत्तर
Given: [Zn2+] = 0.2 M, [H+] = 1.6 M, `"P"_("H"_2)` = 1.8 atm
To find: Emf of the cell `("E"_"cell")`
Formulae:
1) `"E"_"cell"^circ = "E"_"cathode"^circ - "E"_"anode"^circ`
2) `"E"_"cell" = "E"_"cell"^circ - (0.0592 "V")/"n" log_10 [["Product"]]/[["Reactant"]]`
Calculation:
`"Zn"_(("s")) -> "Zn"_((0.2 "M"))^(2+) + 2"e"^(-)` (oxidation at anode)
`2"H"_((1.6 "M"))^+ + 2"e"^(-) -> "H"_(2(1.8 "atm"))` (reduction at cathode)
___________________________________________________
`"Zn"_(("s")) + 2"H"_((1.6 "M"))^+ -> "Zn"_((0.2 "M"))^(2+) + "H"_(2(1.8 "atm"))` (overall reaction)
`"E"_("H"_2)^circ = 0.0 "V" and "E"_("Zn")^circ` = - 0.763 V
Using formula (i),
`"E"_"cell"^circ = "E"_"cathode"^circ - "E"_"anode"^circ`
`"E"_"cell" = "E"_("H"_2)^circ - "E"_("Zn")^circ`
= 0.0 V - (- 0.763 V) = 0.769 V
Using formula (ii),
The cell potential is given by
`"E"_"cell" = "E"_"cell"^circ - (0.0592 "V")/2 log_10 [["Product"]]/[["Reactant"]]`
= 0.763 - `(0.0592 "V")/2 log_10 ((0.2)(1.8))/(1.6)^2`
= 0.763 + 0.0252 = 0.7882 V
The emf of the cell is 0.7882 V.
APPEARS IN
संबंधित प्रश्न
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:
Predict whether the following reaction would occur spontaneously under standard state condition.
`2"Br"_(("aq"))^(-) + "Sn"_(("aq"))^(2+) -> "Br"_(2("l")) + "Sn"_(("s"))`
What is cell voltage?
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 ______.
Calculate E.M.F. of following cell at 298 K Zn(s) |ZnSO4 (0.01 M)| |CuSO4 (1.0 M)| Cu(s) if \[\ce{E^0_{cell}}\] = 2.0 V.
Calculate \[\ce{E^0_{cell}}\] for the following cell.
\[\ce{Cr_{(s)} | Cr^{3+}_{( aq)} || Fe^{2+}){( aq)} | Fe_{(s)}}\]
Given: `"E"_("Cr"^(3+)//"Cr")^0` = −0.74 V,
`"E"_("Fe"^(2+)//"Fe")^0` = −0.44 V
The reduction potential of a half-cell consisting of nickel electrode in 0.1 M NiSO4 solution at 25°C is ____________.
(E0 = −0.257 V)
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 tendency of an electrode to lose electrons is known as ______
Answer the following in one or two sentences.
What is the standard cell potential for the reaction?
\[\ce{2Al(s) + 3Ni^{2⊕}(1M) -> 2Al^{3⊕}(1 M) + 3Ni(s)}\]
if \[\ce{E{^{\circ}_{Ni}}}\] = −0.25 V and \[\ce{E{^{\circ}_{Al}}}\] = −1.66 V?
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:
Write net cell reaction.
Write the value of `(2.303 RT)/F` in the Nernst equation?
Standard potential (E°) of
\[\mathrm{Zn_{(aq)}^{+2}+2e^{-}\longrightarrow Zn_{(s)}~is~-0.76~V}\]
What is standard potential of reaction
\[2\mathrm{Zn}_{(\mathrm{s})}\longrightarrow2\mathrm{Zn}_{(\mathrm{aq})}^{+2}+4\mathrm{e}^{-}\] ?
If \[\mathrm{E^o\left(Cd_{(aq)}^{+2}|Cd_{(s)}\right)=-0.40~V}\]. What is potential for \[\mathrm{Cd}_{(s)}\xrightarrow{}\mathrm{Cd}_{(aq)}^{+2}\left(0.01\mathrm{M}\right)+2\mathrm{e}^{-}\] at 298 K?
Which from following formulae is used to obtain value of E°cell for a reaction taking place in Dry cell?
The cell potential for the following cell notation is approximately:
M(s) | M3+ (aq, 0.01 M) || N2+ (aq, 0.1 M) | N(s)
`E_(M^(3+)//M)^0` = 0.6 V and `E_(N^(2+)//N)^0` = 0.1 V
