Section-D: Comprehension Type
n-factor is very important in redox as well as non-redox reactions. With the help of n-factor we can predicts the molar ratio of the reactant species taking part in reactions. The reciprocal of n-factor’s ratio of the reactants is the molar ratio of the reactants.
In general n-factor of acid/base is number of moles of H+/OH– furnished per mole of acid/base. n-factor of a reactant is no. of moles electrons lost or gained per mole of reactant.
Example 1 :
1. In acidic medium : KMnO4(n = 5) → Mn2+
2. In neutral medium : KMnO4 (n = 3) → Mn2+
3. In basic medium : KMnO4(n = 1) → Mn6+
Example 2 :
FeC2O4→Fe3+ + 2CO2
Total no. of moles of e– lost by 1 mole of FeC2O4
= 1 + 1 × 2 ⇒ 3
∴ n-factor of FeC2O4 = 3
H3PO2 + NaOH → NaH2PO2 + H2O What is the equivalent weight of H3PO2? (mol.wt. is M)
For the reaction,
H3PO2 + NaOH → NaH2PO2 + H2O
What is the equivalent weight of H3PO2? (mol.wt. is M)