how to calculate n - factor in redox reactions

n- Factor Calculation
Acids

Acids are the species which furnish H+ions when dissolved in a solvent.

For acids, n-factor is defined as the number of H+ions replaced by 1 mole of acid in a reaction. Note that the n-factor for acid is not equal to its basicity; i.e. the number of moles of replaceable H+ atoms present in one mole of acid.

For example, n-factor of HCI = 1,

n-factor of HNO3= 1,

n-factor of H2SO4= 1 or 2, depending upon extent of reaction it undergoes.

H2SO4+ NaOH → NaHSO4+ H2O

Although one mole of H2SO4ahs 2 replaceable H atoms but in this reaction H2SO4has given only one H+ion, so its n-factor would be 1.

H2SO4+ 2NaOH → Na2SO4+ 2H2O

The n-factor of H2SO4in this reaction would be 2.

Similarly,

n-factor of H2SO3= 1 or 2

n-factor of H2CO3= 1 or 2

n-factor of H2PO4= 1 or 2 or 3

n-factor of H3PO3= 1

Bases

Bases are the species, which furnish OH–ions when dissolved in a solvent. For bases, n-factor is defined as the number of OH–ions replaced by 1 mole of base in a reaction. Note that n-factor is not equal to its acidity i.e. the number of moles of replaceable OH–ions present in 1 mole of base.

For example,

n-factor of NaOH = 1

n-factor of Zn(OH)2= 1 or 2

n factor of Ca(OH)2= 1 or 2

n factor of AI(OH)3= 1 or 2 or 3

n factor of NH4(OH) = 1