The sum of powers to which of the concentration terms are raised in the rate law is called molecularity of the reaction.

Answer

To solve the question, we need to clarify the concepts of molecularity and order of a reaction in the context of chemical kinetics. Here’s a step-by-step breakdown:

### Step 1: Understanding Rate Law
- The rate law expresses the rate of a chemical reaction in terms of the concentration of reactants. It is generally written as:
\[ \text{Rate} = k [A]^m [B]^n \]
where \( k \) is the rate constant, \( [A] \) and \( [B] \) are the concentrations of the reactants, and \( m \) and \( n \) are the orders of the reaction with respect to each reactant.

### Step 2: Defining Order of Reaction
- The order of a reaction is defined as the sum of the powers to which the concentration terms are raised in the rate law. In our example, the overall order of the reaction would be \( m + n \).

### Step 3: Clarifying Molecularity
- Molecularity refers to the number of reactant molecules that are involved in the rate-determining step of a reaction. It is a theoretical concept and is not determined by the concentrations or their powers in the rate law. For the reaction \( A + B \rightarrow \text{Products} \), the molecularity is 2, as two reactant molecules are involved.

### Step 4: Analyzing the Statement
- The statement in the question claims that "the sum of powers to which the concentration terms are raised in the rate law is called molecularity of the reaction." This is incorrect because:
- The sum of the powers (i.e., \( m + n \)) represents the overall order of the reaction, not the molecularity.
- Molecularity is defined based on the number of molecules participating in the reaction, not the powers in the rate law.

### Conclusion
- Therefore, the statement is false. The correct terminology is that the sum of the powers in the rate law reflects the order of the reaction, while molecularity refers to the number of reactant molecules involved.

### Final Answer
The statement is false because the sum of powers in the rate law refers to the order of the reaction, not the molecularity.

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