Redox (reduction–oxidation, pronunciation: RED-oks or REE-doks) is a type of chemical reaction in which the oxidation states of atoms are changed. Redox reactions are characterized by the actual or formal transfer of electrons between chemical species, most often with one species (the reducing agent) undergoing oxidation (losing electrons) while another species (the oxidizing agent) undergoes reduction (gains electrons). The chemical species from which the electron is removed is said to have been oxidized, while the chemical species to which the electron is added is said to have been reduced. In other words:
Oxidation is the loss of electrons or an increase in the oxidation state of an atom, an ion, or of certain atoms in a molecule.
Reduction is the gain of electrons or a decrease in the oxidation state of an atom, an ion, or of certain atoms in a molecule (a reduction in oxidation state).Many reactions in organic chemistry are redox reactions due to changes in oxidation states but without distinct electron transfer. For example, during the combustion of wood with molecular oxygen, the oxidation state of carbon atoms in the wood increases and that of oxygen atoms decreases as carbon dioxide and water are formed. The oxygen atoms undergo reduction, formally gaining electrons, while the carbon atoms undergo oxidation, losing electrons. Thus oxygen is the oxidizing agent and carbon is the reducing agent in this reaction.Although oxidation reactions are commonly associated with the formation of oxides from oxygen molecules, oxygen is not necessarily included in such reactions, as other chemical species can serve the same function.Redox reactions can occur relatively slowly, as in the formation of rust, or much more rapidly, as in the case of burning fuel. There are simple redox processes, such as the oxidation of carbon to yield carbon dioxide (CO2) or the reduction of carbon by hydrogen to yield methane (CH4), and more complex processes such as the oxidation of glucose (C6H12O6) in the human body. Analysis of bond energies and ionization energies in water allow calculation of the redox potentials.
Homework Statement
Balance the following redox equation.
KMnO4(aq) + H2S (aq) + H2SO4(aq) --> K2SO4 (aq) + MnSO4(aq) + S(s)
Homework Equations
Knowledge of oxidation numbers etc.
The Attempt at a Solution
I simply just cannot figure out where to start and would like basic...
Not particually a paradox, just liked the word play. Anyway...
The definition of a redox reaction is a reaction with both reduction and oxidation. As we know, oxidation is loss, reduction is gain of electrons. So redox is a reaction with both loss and gain of reaction.
Does it follow that...
Because if redox is the transfer of electrons between atoms, and ionic bonding is when one or more electrons go are transferred from one atom to another, wouldn't that mean it is basically a redox reaction?
Homework Statement
I have two problems-
1) Given the cell-
Mn(s)|MnCl2(c1)|HCL(c2)|O2(p atm)|Pt
How do we write the chemical equation taking place at cathode?
Is it H2O ------> 2e + 2H+ + 0.5O2 ?
How do we identify the reaction?
2) Write the half cell involving the reaction -
Cr2O72-(aq)...
Hi just wondering if you could help, I've stumbled across an example question where the iron purity is meant to be above 80% when
8H+ + 5Fe2+ + MnO4- → 5Fe3+ + Mn2+ + 4H2O
15cm3 is titrated and concentration of potassium permanganate used is 0.02M
So far I have worked out
Number...
Homework Statement
How many molecules of hydrogen peroxide were in the whole bottle?
(See Data)
Homework Equations
Data.
Balanced equation.
6H+ + 2Mno4- + 5 h2o2 --> 2Mn2+ + 5O2 + 8 H2O
I used 26.85 mL of MnO4- the first trial, and 29.80 mL in the second trial.
10.000 g of H2O2 used in the...
Homework Statement
Equation 1 - IO3- (aq) + 6 H+ (aq) + 5 I- (aq) -> 3 I2 (aq) + 3 H20
The iodine formed will react with the ascorbic acid.
Equation 2 - C6H8O6 + I 2 -> C6H6O6 + 2 I- (aq) + 2 H+ (aq)
The goal is to determine the ascorbic acid concentration (mg/mL) in a Vitamin C solution. A...
To determine the concentration of Fe (aq)2+ by a redox titration, we could use an acidified
standard solution of
A. Sn2+
B. Pb2+
C. HCl
D. H2O2
I know the answers H2O2, but i don't know how to get it. How doe redox titrations work?
I have read a little bit about some industries deaerating water used in boilers made of iron to prevent them from becoming damaged.
I think this is because removing dissolved oxygen from the water lowers its redox potential. I think that this works because once the redox potential of the...
Homework Statement
A mass of iron ore weighing 0.2792g was dissolved in dilute acid and all the iron was converted to Fe2+(aq). The iron II solution required 23.30ml of 0.0194M KMnO4 for titration. Calculate the percentage of iron in the ore.Homework Equations
Wrote out my redox reactions...
For a reaction where the electric potential is positive, does there need to be something to provide voltage for the reaction to occur? Let's say E= 1.34V for the reaction. Do I need to connect the electrode terminals to a battery to provide 1.34V?
Seems like a strange question, but it just appeared on one of my tests. My guess would be redox, but what is the logic behind the answer?
Thanks for the help!
Homework Statement
Give the net ionic equation for this reaction:
Fe(NH4)2(SO4)2.6H2O + KMnO4
Homework Equations
Reducing reaction is
4H+ + MnO4- + 3e ---> MnO2 + 2H2O
Oxidation
3Fe+2 ---> 3Fe+3 + 3e
The Attempt at a Solution
4H+ + MnO4- + 3Fe+2 ---> MnO2 + 2H2O +...
Homework Statement
I'm working on redox tables and I'm really confused. I know how to write out the half reactions, but i don't understand how you tell which is the strongest oxidizing agent or the weakest. Same thing with reducing agents which is strongest or weakest? Help please...
Homework Statement
Cr(OH)3(s) + ClO3−(aq) ® CrO42−(aq) + Cl−(aq) (basic)
I am up the point where I need to balance both half-reactions for electron charge and I'm confused as to why this half reaction: ClO3− + 6H+ + 6e− ® Cl− + 3H2O, has a total of 6 electrons instead of...
Homework Statement
Balance the following red-ox reaction that occurs in acidic solution.
Homework Equations
Pb(s) + PbO_{2}(s) + H_{2}SO_{4}(aq) \rightarrow PbSO_{4}(s)
The Attempt at a Solution
I did not see a change of oxo state from the sulfur, oxygen, or hydrogens. The lead...
Homework Statement
Calculate the value of the equilibrium constant at 25 degrees celsius for the following reaction:
5Fe2+ + MnO4- + 8H+ ----) 5Fe3+ + Mn2+ + 4H2O
Homework Equations
The equation above is the product of these redox reactions:
1) MnO4- + 8H+ + 5e- ----) Mn2+ + 4H2O E=...
Homework Statement
Determine acid concentration of a mixture of (COOH)2 and H2SO4 by titration against NaOH
Concentration of NaOH = 0.2M
Average Titre Figure (NaOH) = 8.93cm3
Volume of mixture added = 10mL
Homework Equations
2NaOH + (COOH)2 \rightarrow 2NaCOO + 2H2O
The Attempt at...
Hi, I just learned about oxidation and reduction reactions and I have some questions.
Are all ionic reactions redox reactions?
Do elements that make up covalent compounds always have an oxidation number of zero because they only share electrons, not give or take? That is what I was thinking...
OF2 --> F- + O2 + H2O
OF2 --> F-
2H+ +OF2 --> 2F- + H2O
2H+ +OF2 + 4e- --> 2F- + H2O
This is as far as I can get. I don't know how to do the other half of the redox since the equation would be:
OF2 --> O2 + H2O
What do I do here? Maybe I am not setting this up correctly?
Homework Statement
Balance the following redox reactions occurring in an acidic solution.
Homework Equations
PbO2(s)+I-(aq)---->Pb2+(aq)+I2(s)
The Attempt at a Solution
1.) half reactions:
a.) reduction: I-(aq)----->I2(s)
b.) oxidation: PbO2(s)------>Pb2+(aq)
2.) balance...
Homework Statement
In the lab, i saw that when Mg(s) attach with Fe(s) nail in a yellow solution( probably indicator), after one day, the brown substance and bubble are formed.
My net ionic equation is
SOA: O2(g) +2H2O(l) +4e -->4OH-
SRA: Mg(s) --> Mg2+ +2e
NIE: O2(g) +2H2O(l) +2Mg(s)-->4OH-...
I'm having a lot of trouble with this problem!
What mass of lead sulfate is formed in a lead-acid storage battery when 1.34 g of Pb undergoes oxidation?
the answer needs to be in grams
Homework Statement
Write the net ionic equation for H2SO4(aq) to the KMnO4(aq)Homework Equations
The Attempt at a Solution
I am confused on which one should i write.
The first method is to list all the species, then use the data book to find which one is the strong OA and SRA. Multiply one or...
I was taught in high school that all reactions are governed by the valence electrons. of the atoms involved.
Then I was taught that the term "redox reaction" applied only to rxns where e- were exchanged, or oxidation numbers were changed.
But the first fact would lead me to believe that...
Homework Statement
a 0.245 mol/L silver chloride solution is mixed with 50.0 mL of 0.200 mol/L zinc iodide solution. what volume of silver chloride solution is needed for a complete reaction?
(answer is 81.6mL)
Homework Equations
The Attempt at a Solution
Ag+ is the strongest OA,
I- is the...
We have been given the task to write a feature article for a magazine such as new scientist on an area of interest within the following fields:
-Reduction and oxidation
-Electrochemistry
-Electrowinning
I cannot find anything that interests me and has enough relevant information to start...
Homework Statement
HIO3 + FeI2 + HCl ==> FeCl3 + ICl + HOH
Homework Equations
Directions say it's in an aqueous solution, and HCl is a reactant, so you can add H2O and H+ to balance, right?
The Attempt at a Solution
I first found all the oxidation states:
HIO3
H = +1
I = +5
O...
iron(ii) can be determined by redox titration with a cerium (iv) solution. the oxidation reduced reaction is fe2+ + ce2+ = fe3+ + ce3+
what is the concentration of fe2+ if it requires 21.35mL of .3136 ce4+ to titrate a 10.00mL aliquot to the endpoint.
Homework Statement
Which is the reducing agent in this equation, if any?
Cr2O7 2- + 2OH- --> 2CrO4 2- +H2O
Homework Equations
The Attempt at a Solution
After giving the elements their oxidation numbers I found the reducing agent to be Cr2O7 2-
Is this correct?
Hi there,
I have some trouble understanding redox reactions. Here is the question:
Sulphuric acid is one of the strongest inorganic acides which in some reaction shows oxidation properties. In which of reactions below, sulphuric acid acts as oxidating tool?
A.
\text{H}_2{SO}_4 +...
Homework Statement
Balance the equation (Note: the coefficients provided may be wrong):
3 Co(s) + 8 H+(aq) + 8 NO3-(aq) → 3 Co2+(aq) + 6 NO3-(aq) + 2 NO(g) + 4 H2O(l)
The Attempt at a Solution
I started out by doing a half reaction
Co → Co 2+ +2e- This...
Hey guys, I'm really new to Redox reactions so any help is greatly appreciated. How do I identify the oxidizing and reducing agents from the chemical equation;
3N2H4 --> 4NH3 + N2
Why is it that the agents are products of the equation, shouldn't they be the reactants? I'm also not really...
Homework Statement
hey guys this question looks easy, but I am confused? any help/tips would be appreciated
Which of the following is the best reducing agent?
Cl2 + 2e- 2Cl-; E° = 1.36 V
Mg2+ + 2e- Mg; E° = -2.37 V
2H+ + 2e- H2; E° = 0.00 V
Homework Equations
The...
Homework Statement
0.9966g of Iron Wire was used...
Iron Wire was placed in 200cm3 of 1m Sulphuric Acid, this was heated and the hydrogen gas vented off...
Producing...
Fe + H2SO4 = FeSO4 + H2
Fe = Iron
H2SO4 = Sulphuric Acid
FeSO4 = Ferrous Sulphate
H2 = Hydrogen
This...
I have a chemical practical coming up in a few weeks time and need help sussing out some questions. I know that the practical will be on redox titration between h2o2 and KMnO4, I wanted to know how I could determing the concentration of h2o2. Could someone run through a specimen calculation...
If a 2.893 g sample of an unknown containing iron requires 28.45 mL of the permanganate solution described in Pre-Laboratory question 3 to reach the endpoint what is the % Fe in the unknown?
Homework Statement
You are provided with a solution of hydrogen peroxide which is known to be approximately ‘100-volume’. Plan two experiments that would enable you to determine the exact concentration of H2O2 in mol dm-3, in this solution. One of your experiments should involve a redox...
Homework Statement
Bleaching powder, Ca(OCl)Cl, reacts with iodide in acidic medium according to the equation:
OCl– + 2 I– + 2 H3O– ---> I2 + Cl– + 3 H2O
How many millilitres of 0.0645 M Na2S2O3 are required to titrate the iodine liberated from a 0.6028 g sample of bleaching powder...
I have read about 20 explanations and tutorials and heard people talk about reducing and oxidizing compounds countless times but the concept continues to elude me. I know that oxidizing has 3 meanings but in this case it refers to one compound taking electrons off another compound and reduction...
Homework Statement
How many electrons are transferred in the following reaction?
6 Br^- (aq) + Cr2O7^2- (aq) + 14 H^+ --> 2Cr^3+ (aq) + 7H2O + 3Br2 (l)
a) 1
b) 2
c) 3
d) 6
e) 14
Homework Equations
The Attempt at a Solution
Redox reactions really confuse me, but I gave it a...
The redox midpoint potential (Eo’) of NAD+/NADH at pH 7.0 is -320 mV. If the total concentration of {[NAD+] + [NADH]} is 1.5 mM in cells, and the cellular redox potential is about -200 mV, what are the concentrations of [NAD+] and [NADH], respectively? Under certain oxidative stress...
Homework Statement
Suppose 1.00g of Mn Reacts with an excess of 6.00M HCl, how many grams of H2 gas is produced?
What volume hydrogen gas is produced by this reaction?
Homework Equations
density of hydrogen gas is 0.08988g/L
conditions: 0 degrees celsius, 1 atm pressure
The...
Homework Statement
OCl- is reacted with I- in acidic solution to generate I2.
The I2 generated is then titrated using a solution of Na2S2O3.
If you look at the sum of the two reactions above, information about S2O3- can be used to determine the amount of I2 and thus the amount of ClO-...
Homework Statement
1. Explain why the following chemical reaction would not be effective to determine [Fe2+] in a given solution.
Fe2+ (aq) + H2O2 (aq)-> Fe3+ (aq)+ H2O(l) | in acidic solution
Homework Equations
The Attempt at a Solution
Hello:
I am thinking that there may be a lack of...
H2SO4 (aq) + 2HI (aq) --> SO2 (g) + I2 (s) + 2H2O (l)
Indicate the oxidizing and reducing agents.
-----------------------------------------------------
I started by assigning oxidation numbers to all the atoms:
H=+1
O=-2
S=+6 to +4
I=-2 to 0
I think H2SO4 is the reducing agent and...