Questions tagged [reduction-potential]

For questions about the reduction potential (A measure of the tendency of a chemical species to acquire electrons and thereby be reduced) or its applications. Also see the tag [electrochemistry].

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3
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2answers
191 views

contradiction between Gibbs energy variation and redox potential

Let's consider the following two redox reactions; $\ce{C_2H_4O_2 + 2\;O_2 -> 2\;HCO_3^- + 2\;H^+}$ $\ce{C_2H_4O_2 + 1.6\;NO_3^- -> 2\;HCO_3^- + 0.8\;N_2 + 0.8\;H_2O + 0.4\;H^+}$ Considering ...
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1answer
774 views

Why does oxidation of the electrode take place in a solution?

What makes the electrode atoms start to ionize? Perhaps because of the solutes in the solvent? So probably if you place it in distilled water it will not ionize, right? Follow up question: If the ...
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1answer
67 views

How to know the ionization power of an unknown metal? - difficult

Imagine having the 4 following beakers: where P, Q, R and S are metallic plates. In beaker 1 and beaker 2 nothing happens. However in beaker 3 and 4 the metalic pieces become thinner. How would you ...
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1answer
64 views

How to calculate whether a redox reaction is spontanuous?

I have some difficulties to apply the basic concepts of calculating whether a reaction is spontanuous or not. given: $$\ce{H_2SO_3(aq) + 2Mn(s) +4H^+(aq) -> S(s) + 2Mn^{2+}(aq) +3H_2 O(l)}$$ and ...
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understanding redox reaction

I am a total noob in chemistry, so sorry in advance if this is a very stupid question... I am trying to solve this redox reaction: $$\ce{KClO3 + FeSO4 + H2SO4 -> Fe2(SO4)3 + KCl}$$ $$\ce{K^{+1}Cl^{...
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543 views

Can a more electropositive metal replaced by a less electropositive one?

I read from this reference that rubidium is extracted by reduction of its chloride with calcium or sodium. How is it possible?. Their electronegativities are much higher than rubidium. I think ...
2
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1answer
288 views

Calculating Ratio of Stability Constants

Solution I contains a mixture of $\ce{FeCl2}$ and $\ce{FeCl3}$, and solution II contains a mixture of $\ce{K4Fe(CN)6}$ and $\ce{K3Fe(CN)6}$. The concentrations of iron-containing species satisfy the ...
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3answers
2k views

Can hydrogen gas reduce copper(II) ion?

I have a solution of copper(II) sulfate, and I would love to precipitate the copper metal. From looking at the standard reduction potential table, it appears that I can do this by bubbling hydrogen ...
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1answer
39 views

Why are electrochemical cell potentials the same for reactions with same overal equation?

Why are cell potentials the same for reactions with same overal equation? e.g. hydrogen-oxygen fuel cell in acidic and alkaline conditions It is from the chemistry past paper
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0answers
493 views

Electrolysis of dilute and concentrated sodium chloride and the Nernst equation

Interested to know if there is a critical concentration at which $\ce{Cl-}$ will oxidise over $\ce{H2O}$ and if this can be determined using the Nernst equation. That is, obviously if $[\ce{Cl-}]>...
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2answers
231 views

How to calculate the pH of a redox reaction between nickel(IV) oxide and silver?

For the following reaction: \begin{gather} \ce{NiO2(s) + 4 H+(aq) + 2 Ag(s) -> Ni^2+(aq) + 2H2O(l) + 2Ag+(aq)}\\ E^\circ = \pu{2.48 V} \end{gather} Calculate the $\mathrm{pH}$ of the solution if $E ...
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225 views

Why does chromium metal not react with a solution of Mg^2+ even though their standard cell potentials produce a net positive voltages?

Write net equations for the spontaneous redox reactions that occur during the following or NONE if there is no extensive reaction. Use the lowest possible coefficients. Include states-of-matter under ...
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2answers
7k views

Best oxidizing and reducing agents: Na, Zn^2+, Ba, Ba^2+, and Ag?

Which is the best oxidizing agent and the best reducing agent from the species listed below? $\ce{Na,~Zn^2+,~Ba,~Ba^2+,~Ag}$ I determined that oxidizing agent as $\ce{Zn^2+}$ because it appears on ...
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238 views

Comparison of standard reducing potential of Co3+ and Mn3+ [duplicate]

$\ce{Co^3+(aq) + e- → Co^2+(aq)}$ +1.81 V $\ce{Mn^3+(aq) + e- → Mn^2+(aq)}$ +1.51 V This is the data of Standard reducing potentials I have found on internet. Why is reducing potential of $\ce{Mn^...
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1answer
560 views

Prevention of rusting

I'm currently learning about corrosion prevention, and have a question regarding galvanising. Say that you have an iron nail. You galvanise it (coat it in zinc), so that is doesn't rust by preventing ...
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1answer
462 views

What else other than zinc can reduce Cr(III) to Cr(II)?

I successfully completed the synthesis of bis(chromium(II)hydrate)tetraacetate (aka chromous acetate) using zinc as the reducing agent. For my lab report, I was asked to suggest at least two other ...
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2answers
807 views

Can molten aluminium be used to reduce iron oxide (rust) into iron?

Will surface rust on an iron crucible be converted if used to melt aluminium? Can one convert bog/lake iron ore into iron using molten aluminium similar to the Thermite reaction? Or perhaps the ...
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1answer
26 views

REDOX spontaneity using electrode potentials

For this question, I thought the correct answer is A, because if we look at the electrode potential, that of iron(III) is higher than that of iodine, therefore the equilibrium for $\ce{Fe^3+}$ will ...
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1answer
192 views

Electrochemistry

My book says: "At each electrode-electrolyte interface there is a tendency of metal ions from the solution to deposit on the metal electrode trying to make it positively charged. At the same ...
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3answers
37k views

Why is the reaction between potassium permanganate and hydrogen peroxide spontaneous?

When hydrogen peroxide is mixed with potassium permanganate, oxygen gas and water vapour are formed, according to the reaction (source): $$\ce{2MnO4- + 3H2O2 -> 2MnO2 + 2H2O + 3O2 + 2OH-}$$ This ...
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1answer
11k views

Which half cell equation do you switch when calculating E° cell?

Given the following standard potentials calculate the overall $E^\circ_\mathrm{cell}$: $$ \begin{align} \ce{Pb(SO4)(s) + 2 e- &→ Pb(s) +SO4^2-(aq)} &\quad E^\circ &= \pu{-0.356 V} \\ \ce{...
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2answers
3k views

Will magnesium undergo a redox reaction with zinc(II) or copper(II)?

Magnesium can do a redox reaction with $\ce{Cu^2+}$ as well as with $\ce{Zn^2+}$, since Mg has the lowest reduction potential $E_0$. (I am aware that a reaction may or may not be feasible as redox, ...
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1answer
815 views

What are the products in a reaction between a metal and an acid?

When magnesium metal and hydrochloric acid react, hydrogen gas is released (and not chlorine gas). However, when metals such as copper is placed in nitric acid, NO(g) is released and not hydrogen. So, ...
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361 views

Complete Oxidation and Redox Equations for Sacrificial Galvanic Anode

I'm trying to get a more complete picture of how the chemistry works within a typical marine setup including a sacrificial anode. The setup consists of an aluminum hull, another metal (say a stainless ...
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0answers
104 views

Determining Overall Equation and Oxidation Potential

Cell 1 is composed of a reference chloranil half-cell (standardised against SHE as $+0.680 \mathrm{V}$) connected to an $\ce{Ag/AgCl}$ half-cell containing saturated ($0.125\ \mathrm{mol\ L^{−1}}$) $\...
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1answer
2k views

Why are alkali hydrides strong reducing agents?

My book says that alkali hydrides are strong reducing agents. It also says that this is especially true at high temperatures? Is there any particular reason behind it?
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756 views

Cell voltage required for refining copper

If you put Zinc or Iron solids into aqueous copper (II) sulphate solutions, copper solids form spontaneously due to the fact, that Zinc/Iron oxides into ions more willingly than Copper does. And if ...
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0answers
1k views

Why is the electrode potential of copper positive when hydrogen is more electronegative than copper?

Both copper and zinc has an electronegativity that is smaller than hydrogen, but why does copper have a positive electrode potential while zinc has a negative one? And lead (which has a greater ...
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1answer
375 views

How are the chemical reactions of the table of standard reduction potentials experimentally determined?

My background: I've read several books and articles on electrochemistry and even do photoelectrochemical research in a lab, so I'm somewhat familiar with the concepts and techniques. In texts on ...
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4answers
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Why is Cr(2+) a stronger reducing agent than Fe(2+) in water?

According to me, $\ce{Fe^{2+}}$ should be a better reducing agent because $\ce{Fe^2+}$ - after being oxidized - will attain a stable $\ce{d^5}$ configuration, whereas $\ce{Cr^2+}$ will attain a $\ce{d^...
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1answer
7k views

What is the standard potential of carbon?

What's the value of standard potential of carbon? The hydrogen and Carbon are in the electrochemical series despite being non metals hydrogen has zero potential difference what about carbon?
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1answer
174 views

How to identify which of two given electrodes with corresponding solutions is reducing more?

For the sake of the question, let’s assume that you are provided with two labelled rods of the pure metals $\ce{A}$ and $\ce{B}$ and two unlabelled bottles containing $\pu{1.0 mol dm-3}$ aqueous ...
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0answers
269 views

Reduction of vanadyl ion

I want to reduce vanadyl to vanadium (III), can somebody please suggest some appropriate methods for it? I am trying to make a redox flow battery for a project but I have only vanadyl sulfate.
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1answer
1k views

Balancing reduction equations for galvanic cell

Problem: Compute the potential of the following galvanic cell: $$(\ce{Mg (s)} \mid \ce{Mg^2+ (aq)}\ (0.30\ \mathrm{M}) \mid \mid \ce{Sn(OH)4^2- (aq)}\ (0.10\ \mathrm{M}); \mathrm{pH} = 9 \mid \ce{Sn (...
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1answer
298 views

AgI and AgCl reduction potentials

The reduction potential for $\ce{AgI}$ is $-0.15\ \mathrm{V}$ and for $\ce{AgCl}$ it’s $0.22\ \mathrm{V}$. As $nFE =-\Delta{G} = T\Delta{S} - \Delta{H}$ this must imply that $\ce{AgI}$ is a stronger ...
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0answers
1k views

What is the Difference between difference between Standard Electrode Potentials and Standard Reduction Potentials?

As the question suggests I am wondering the difference between standard electrode potentials and standard reduction potentials. I know that they are both a measure of the Voltage from certain ...
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2answers
3k views

Why exactly are standard potentials additive?

I don't really study chemistry so while my question may be very obvious, its not obvious to me. If we take an electrochemical reaction like $$\ce{2Fe^2+ + Au^3+ -> 2Fe^3+ + Au+}$$ we can find its ...
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1answer
763 views

Standard Half-Cell Reduction Potential for Periodate to Iodine

I'm looking for standard half-cell reduction potential $\ce{IO4-}$/$\ce{I2}$ in acid medium. Unfortunately I was unable to find the value in all comprehensible reference books. Hard to believe this ...
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Why is lithium the most reducing alkali metal, and not caesium?

Caesium has a larger size, and the effective nuclear charge that the valence electron experiences will be far less compared to that of lithium's, right? But lithium is still considered the strongest ...
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2answers
249 views

Ways to change the spontaneity of a reaction

I can think of any other way to influence the value of $\Delta G$ than (1) change the temperature (2) providing an external source to overcome the negative cell potential The relationship between $\...
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1answer
2k views

Is reduction potential equivalent to the ease of discharge?

Loosely speaking, is the reduction potential equivalent to the ease of discharge in the context of electrolysis? i.e. is it easier to discharge an ion with a higher reduction potential as opposed to ...
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2answers
11k views

Why is Cr²⁺ is a good reducing agent but Mn³⁺ is a good oxidising agent? [duplicate]

The question is the same as the title states. In my textbook,[NCERT Chemistry I for Class 12 , pg no 217.] the following is written $\ce{Cr^{2+}}$ gets converted to $\ce{Cr^{3+}}$ as the +3 oxidation ...
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1answer
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Principle of potentiometric titration

In potentiometric titration between ascorbic acid and iodine, when we plot the graph of EMF with volume of iodine consumed, we get a sudden decrease in EMF at equivalance point--why? It is also ...
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1answer
757 views

Iodometric titration of copper – standard electrode potentials

Upon inspection of the standard electrode potentials for the half reactions for both $\ce{Cu^2+}$/$\ce{Cu+}$ and $\ce{I2}$/$\ce{2I-}$, it becomes apparent it should be the iodide ions that act as the ...
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1answer
667 views

What is the meaning of electrode potential?

When we say that the electrode potential for $\ce{Co}^2$$^+$/$\ce{Co}$ is -0.28 V and $\ce{Cu}^2$$^+$/$\ce{Cu}$ +0.337 V, what is the physical meaning? Can you conceptually explain when two electrons ...
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1answer
383 views

Implicit dependence of reaction rate through reduction potential and activation energy

On one hand, the larger the reduction potential of a chemical reaction and the smaller its activation energy, the larger the reaction reaction. on the other hand the rate of a reaction depends on ...
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1answer
383 views

How to find the potential of a mixed Iron/ Cer solution?

Given the following half-reactions: \begin{align} \ce{Ce^{4+} + e^{−} &-> Ce^{3+}} & E° &= \pu{1.72 V}\\ \ce{Fe^{3+} + e^{−} &-> Fe^{2+}} & E° &= \pu{0.771 V}\\...
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1answer
537 views

The spontaneity of a redox reaction

Suppose we have a redox reaction and we want to see in what direction the reaction is spontaneous. We do this by comparing the standard reduction potentials of the sub-reactions available in the main ...
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1answer
758 views

On Spontaneity of the Redox Reactions

According to this Mc Graw-Hill link during a spontaneous redox reaction Gibbs Free Enthalpy must decrease and at the same time the change in the Gibbs Free Enthalpy is the maximum electric work that ...
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3answers
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Why is standard reduction potential an intensive property?

My book says that Since the number of electrons lost must equal the number gained, the half-reactions must be multiplied by integers as necessary to achieve the balanced equation. However, the ...