Dear manisha, Though these two terms are used often interchangeably, reactant and reagent are not the same. Reactant is the same as a substrate of chemical reaction involved in product formation. While reagent is considered as additional compound that causes chemical reaction (i.e. catalyst may be considered as reagent) or is used for analytical analysis of the reaction (i.e., Fehling's reagent used for differentiation of carbohydrate and ketone groups).
thanks for the answer .....so i.e mean reagent and reactant are different please explain with example.