Q.How do nature of the reactant influence rate of reaction.

Step 1. Every reaction requires breaking some of the reactant's existing bonds and forming new ones; the net energy this needs depends on the specific chemical NATURE of the reactant, so different reactants react at genuinely different rates under otherwise identical conditions.

Step 2. Example: oxidation of $Fe^{2+}$ (from ferrous ammonium sulphate) by $KMnO_4$ proceeds readily at room temperature, while oxidation of oxalate ion by the SAME $KMnO_4$ is distinctly slower, needing external heating to about $60^\circ$C to proceed at a workable rate.

Step 3. Physical STATE matters too: gas-phase reactions are generally faster than reactions involving solid or liquid reactants, since gas molecules move and collide far more freely. Sodium reacts faster with iodine VAPOUR than with solid iodine. …

Explain the two aspects of 'nature' the book distinguishes -- chemical identity (bond energy) and physical state (gas/l …

• Discussing only chemical identity (bond strength) while omitting the equally important physical-STATE effect (gas vs solid/liquid rea …