Balancing REDOX in acids and alkali

OCl- in acid conditions goes to Cl2

2OCl- + 4H+ + 2e- --> Cl2 + 2H2O



OCl- in alkali conditions Cl-

OCl- + 2H+ + 2e- + 2OH- --> Cl- + H2O

OCl- + H2O + 2e- --> Cl- + 2OH-

Calculating Eo cell

Balancing REDOX equations in acidic conditions

Standard electrode (reduction) potentials

These are a measure of how easy a REDOX half reaction undergoes reduction and can be used to predict if voltage will be generated for a given combination and can be looked up in a data booklet.

The more positive the Eo value the easier the half reaction will undergo reduction.

Electrochemical cell diagrams

Electrolysis vs Electrochemical cells.

Electrolysis

Copper + Chlorine gas --> copper chloride (spontaneous reaction)

Copper + Chlorine gas <-- Copper chloride (non-spontaneous reaction)
electrolysis


Electrochemical cells

This works by combining two REDOX half cells containing metals of different reactivity.

example: Zn/Zn2+ half cell connected to a Cu/Cu2+ half cell.

When these two half cells are connected, the Zn half cell undergoes oxidation because Zn is more reactive that Cu.

Zinc half cell:

Zn --> Zn2+ + 2e- -this is oxidation, LEOA, anode, and will be negative as electrons are being released.

Copper half cell:

Cu2+ + 2e- --> Cu -this is reduction, GREC, cathode, and will be positive.

Potassium Permanganate in acid, alkali and neutral conditions

Welcome to Year 13 Chemistry 2010

This blog is set up as a place where we can put tip-bits of information, webcasts and other exciting class experiences that will hopefully be useful when you come to revise.