The rate of reaction is measured either by an increase in the amount of………..or by a decrease in the amount of…………per unit interval of……………. .

Answer

To solve the question regarding the measurement of the rate of reaction, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Rate of Reaction**: The rate of a chemical reaction can be defined as the change in concentration of reactants or products over time. This means we can measure how quickly a reactant is consumed or how quickly a product is formed.

2. **Identifying the Components**: In a chemical reaction, we typically have reactants that are consumed and products that are formed. For example, in a reaction where reactant A converts to product P, we can measure the rate of reaction by observing changes in the amounts of A and P.

3. **Rate Expression**: The rate of reaction can be mathematically expressed. For reactants, it is often represented as:
\[ \text{Rate} = -\frac{d[A]}{dt} \]
where \([A]\) is the concentration of the reactant A, and \(t\) is time. The negative sign indicates that the concentration of A is decreasing as the reaction proceeds.

4. **Product Formation**: Conversely, for products, the rate can be expressed as:
\[ \text{Rate} = +\frac{d[B]}{dt} \]
where \([B]\) is the concentration of the product B. The positive sign indicates that the concentration of B is increasing as the reaction proceeds.

5. **Filling in the Blanks**: Based on the understanding that the rate of reaction can be measured by:
- An increase in the amount of **product** (since products are formed),
- A decrease in the amount of **reactant** (since reactants are consumed),
- Over a unit interval of **time**.

### Final Answer:
The rate of reaction is measured either by an increase in the amount of **product** or by a decrease in the amount of **reactant** per unit interval of **time**.

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