Are there any tips for writing redox reactions?

Answer 1

Start by writing two half reactions. Next, balance the main element. Then balance the oxygens by adding water to the appropriate side. Next balance the hydrogens by adding H+ to the appropriate side. Next balance the charge by adding electrons to the appropriate side. Then combine the two half reactions in such a way that the electrons cancel. If you are in a basic solution, you then add hydroxide ions to both sides of the equation, converting the H+ ions into H2O. For example, if you are given the skeleton equation

Fe(2+) + Cr2O7(2-) --> Fe(3+) + Cr(3+) , start by writing two half reactions:

Fe (2+)--> Fe(3+)

Cr2O7(2-) --> Cr(3+)

Then balance the main element in each half reaction:

Fe(2+)-->Fe(3+)

Cr2O7(2-)-->2Cr(3+)

Next balance the oxygens in each half reaction:

Fe(2+)--> Fe(3+)

Cr2O7(2-) --> 2Cr(3+) + 7H2O

Now balance the hydrogens in each half reaction:

Fe(2+)--> Fe(3+)

Cr2O7(2-) + 14H+ --> 2Cr(3+) + 7H2O

Now balance the charge in each half reaction:

Fe(2+) --> Fe(3+) + e(-)

Cr2O7(2-) + 14H+ +6e(-) --> 2Cr(3+) + 7H2O

Now you want to combine the equations and cancel the electrons, so you multiply the first equation by six and add the equations together:

6Fe(2+) + Cr2O7(2-) + 14H+ +6e(-) --> 6Fe(3+) + 6e(-) + 2Cr(3+) + 7H2O, which is the same as 6Fe(2+) + Cr2O7(2-) + 14H+ --> 6Fe(3+) + 2Cr(3+) + 7H2O.

If you are in acidic solution, you are now done. If you are in basic solution, you need to deal with the H+ ions by adding hydroxide to both sides of the equation.

6Fe(2+) + Cr2O7(2-) + 14H+ + 14OH- --> 6Fe(3+) + 2Cr(3+) + 7H2O + 14OH-, which is 6Fe(2+) + Cr2O7(2-) + 14H2O --> 6Fe(3+) + 2Cr(3+) + 7H2O + 14OH-, or

6Fe(2+) + Cr2O7(2-) + 7H2O --> 6Fe(3+) + 2Cr(3+) + 14OH-

Voila, you're done!

Answer 2

Identify the oxidation numbers of the atoms involved, balance the atoms and charges on each side of the reaction, balance the number of electrons transferred, and balance the reaction by adjusting coefficients. Remember to check the final equation to ensure that the overall charge and mass are balanced. Practice and familiarity with common redox reactions will also help in mastering this skill.

Answer 3

just practice the method 8-9 times u will get perfection....and it will not consume any time afterwards..!!

Answer 4

The oxidation reaction between magnesium metal and oxygen, for example, involves the oxidation of magnesium. 2 Mg(s) + O2(g) -----> 2 MgO(s)