How many milliliters of 0.200 M NaOH are required to completely neutralize 5.00 mL of 0.100 M H 3PO 4?

The oxidizing agent experiences a decrease in oxidation number whole the reducing agent experiences an increase in oxidation number.

Oxidation refers to loss of electrons and the process leads to an increase in oxidation number while reduction has to do with gain of electrons. The reducing agent in a reaction is oxidized while the oxidizing agent is reduced.

For the reaction;

N2(g) + 3H2(g) →2NH3(g)

The element that is oxidized is hydrogen while the element that is reduced is nitrogen.

For the reaction;

3Fe(NO3)2(aq) + 2Al(s) →3Fe(s) + 2Al(NO3)3(aq)

The element that is oxidized is aluminium while the element that is reduced is iron

For the reaction;

Cl2(aq) + 2NaI(aq) → I2(aq) + 2NaCl(aq)

The element that is oxidized is iodine while the element that is reduced is chlorine.

For the reaction;

PbS(s) + 4H2O2(aq) →PbSO4(s) + 4H2O(l)

The element that is oxidized is hydrogen while the element that is reduced is oxygen

Learn more: link