Molecularity is always a whole…………… while the order of reaction may be……………, ……………, ………………., or even zero.

Answer

To answer the question, we need to fill in the blanks with appropriate terms related to molecularity and order of reaction.

**Step 1: Understand the definition of molecularity.**
Molecularity refers to the number of reactant molecules that participate in a single step of a reaction. It is always a whole number because you cannot have a fraction of a molecule participating in a reaction.

**Step 2: Understand the definition of order of reaction.**
The order of a reaction is an experimental quantity that indicates how the rate of reaction depends on the concentration of the reactants. The order can be a whole number, a fraction, or even zero, depending on the reaction mechanism and the way the reactants affect the rate.

**Step 3: Fill in the blanks.**
Based on the definitions:
- Molecularity is always a whole **number**.
- The order of reaction may be **positive**, **negative**, **fractional**, or even **zero**.

Thus, the complete statement is:
"Molecularity is always a whole **number** while the order of reaction may be **positive**, **negative**, **fractional**, or even **zero**."