Oxidizing and Reducing Agents

March 05, 2013

Oxidizing Agents Reducing Agents -are reduced (gain e-) -are oxidized (lose e-)

Examples Examples metals + metal ions (M ) anions (N-) non metals acids

Not all OA's have the same Not all RA's have the same strength. Some are better strength. Some are better at gaining electrons. This at losing electrons. This makes them more reactive. makes them more reactive. (stronger) (stronger) March 05, 2013

Reducing Agents -are oxidized (lose e-)

Examples Oxidizing Agents metals anions (N-)

- Not all RA's have the same -are reduced (gain e ) strength. Some are better at losing electrons. This makes them more reactive. (stronger) Examples metal ions (M+) non metals acids

Not all OA's have the same strength. Some are better at gaining electrons. This makes them more reactive. (stronger)

When an OA is reduced, it becomes an RA

2+ - Cu (aq) + 2e ----> Cu(s)

OA + e- ----> RA March 05, 2013

Example

2- + - SO4 (aq) + 4 H (aq) + 2e ---> H2SO3(aq)

Is H2SO3(aq) an oxidizing agent or a reducing agent?

When a RA is oxidized it becomes an OA

2+ - Pb(s) ---> Pb (aq) + 2e

RA ---> OA + e- March 05, 2013

Rule for Comparing OA and RA strength

If a substance is a strong OA, it is a weak RA in its reduced form. (and vice versa)

OA + e- ---> RA

Example

Reactive metals like sodium are strong reducing agents.

+ Are Na (aq) a weak or strong oxidizing agent? March 05, 2013

Redox Tables A redox table is a series of reduction reactions listed with the strongest OA at the top left

The strongest RA is on the bottom right

The reactions are reversible (can be read forward and backwards March 05, 2013

Your redox table is on page 7 of the data book March 05, 2013

Which is a stronger OA

3+ Br2(l) or Fe (aq)

2- + + SO4 (aq) and H (aq) or Ag (aq) March 05, 2013

Fe2+ can gain electrons or lose electrons (this is common in multivalent metals)

Write the half reaction when Fe2+ is reduced.

Water can act as an OA or an RA. Write the reaction when water acts as an RA.

Is water a weak or strong RA? March 05, 2013

A redox table can be used to determine if an OA and RA will react spontaneously with each other.

Rule for Predicting Sponteneity

An OA and RA will react spontaneously with each other if the OA is above the RA on the redox table

Identify three metals that react spontaneously with nitric acid. March 05, 2013

+ - A salt solution contains Na (aq) and Cl (aq). Do these ions react spontaneously with each other?

Will H2(g) react spontaneously with copper (II) ions

Will H2(g) react spontaneously with lead(II) ions March 05, 2013

bottom half March 05, 2013 March 05, 2013

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