Chemistry

Using a table of standard reduction potentials, determine the best answer to the following questions.

a) Which of the following reagents would oxidize Cr to Cr3 , but not Ag to Ag ?
Choices: Ca^2+, Br2, Co^2+, Ca, Br^-, or Co.

b) Which of the following reagents would oxidize I– to I2, but not Cl– to Cl2?
Choices: Ca^2+, Br2, Co^2+, Ca, Br^-, or Co.

Can someone explain to me how to do this? I don't even know how to start. I got the values but I don't understand how it works.

1. 👍 0
2. 👎 0
3. 👁 1,250
1. You say you've looked up these values. My values won't be the same as yours because I'm using an old book but they will be close. Here is how you do the first one.
Cr==> Cr^3+ + 3e You look in your table and find this potential. It will be listed "backwards" as Cr^3+ + 3e ==> Cr because tables list them as reduction potentials and this is an oxidiation; my book lists it as -0.74 so we write 0.74 for Eo as written.
The second part of the reaction will be
Ca^2+ + 2e --> Ca and that is the way you look it up. My text lists that as -2.8 as a reduction.
We summarize
Cr ==> Cr^3+ + 3e Eo = 0.74
Ca^2+ + 2e ==> Ca Eo = -2.86
-----------------------
So you add these two equations and obtain -2.12v and since it isn't a + voltage you know it won't go as written and now you know Ca^2+ ion will not oxidize Cr to Cr^3+. You go through the others in the list and find those that give a + voltage. When you have found the one (or ones) that fit the criteria of oxidizing Cr to Cr^3+, you apply that information with the Ag ==> Ag^+ and find those that will oxidize Cr but not Ag.

b is done exactly the same way but with two different half reactions.

1. 👍 0
2. 👎 0
posted by DrBob222

Similar Questions

1. Chemistry

use the appropriate standard reduction potentials in the appendix of your book to determine the equilibrium constant at 285 K for the following reaction under acidic conditions 4H+(aq) + MnO2(s)+2Fe+2(aq)----> Mn+2

asked by Rachel on April 28, 2016
2. chemistry... HELP

Equilibrium constant question!!!? Standard reduction potentials Reduction half-reaction E(V) Ag+(aq) + e- ---> Ag (s) 0.80 Cu ^2+ (aq) + 2e- ---> Cu (s) 0.34 Sn^4+(aq) + 4e- ---> Sn (s) 0.15 2 H+(aq) + 2e- ---> H2 (g) 0 Ni^2+(aq)

asked by Ann on November 3, 2012
3. chemistry

Write the equation for the reaction, if any, that occurs when each of the following experiments is performed under standard conditions. a) crystals of iodine are added to an aqueous solution of potassium bromide. b) liquid bromine

asked by Krystal on May 13, 2007
4. chemistry

I posted this question last night but did not get an answer- I am posting again because I have an exam I am studying for and do not understand this concept! Thanks! Using the given data, and the table of Standard Reduction

asked by kellie on August 3, 2012
5. chemistry

Using the given data, and the table of Standard Reduction Potentials, find the standard reduction potential for this half reaction: 8H^+ + BaCrO4(s) + 3e- -> Ba^2+ + Cr^3+ + 4H2O(l) given: Ksp (BaCrO4)=2.1E-10 DeltaGf* (kJ/mol):

asked by kellie on August 2, 2012
6. chemistry

Consider the following standard reduction potentials of some commonly used metals: ξo (V) Au3+ (aq) + 3 e- → Au (s) +1.50 Ag+ (aq) + e- → Ag (s) +0.80 Cu2+ (aq) + 2e- → Cu (s) +0.34 Fe3+ (aq) + 3e- → Fe (s) -0.036V Al3+

asked by bekah on May 2, 2014
7. Chemistry

Given these standard reduction potentials at 25 C 1. Cr3+ + e- ===> Cr2+ E1=-0.407 V 2. Cr2+ + 2e- ===> Cr(s) E2=-0.913 V determine the standard reduction potential at 25C for the half-reaction equation Cr3+ + 3e- ===> Cr(s) E=?

asked by Bridget on February 23, 2014
8. Chemistry

Calculate the cell potential for the following reaction as written at 25.00 °C, given that [Zn2 ] = 0.842 M and [Ni2 ] = 0.0100 M. Standard reduction potentials can be found here. reaction: Zn(s)+Ni^2+(aq)--->Zn^2+(aq)+Ni(s)

asked by Sophie on May 4, 2014
9. Chemistry

Based on the standard reduction potentials given below, which species is most likely to be oxidized? Ag+ + e- → Ag, Eo= 0.80 V Cu2+ + 2e- → Cu, Eo= 0.34 V Zn2+ + 2e- → Zn, Eo= -0.76 V Cd2+ + 2e- → Cd, Eo= -0.40 V I thought

asked by James on October 12, 2016
10. Chemistry

Using standard reduction potentials, show that one can prepare an ammine complex from CoCl2 and hydrogen peroxide in the presence of ammoinia but not in its absence. (need to write two redux reactions, calculate standard

asked by Anonymous on April 26, 2012

More Similar Questions