In a chemical reaction, two reactants take part. The rate of reaction is directly proportional to the concentration of one of them and inversely proportional to the concentration of the other. The order of the reaction is:

0

The correct answer is option 1. 0.

The order of a reaction is determined by the exponents of the concentration terms in the rate equation.

In this case, the rate of reaction is directly proportional to the concentration of one reactant and inversely proportional to the concentration of the other. This suggests a second-order reaction.

A second-order reaction can be represented by the rate equation:

\(\text{Rate} = k[A]^m[B]^n \)

where \([A]\) and \([B]\) are the concentrations of the reactants, and \(m\) and \(n\) are the exponents that determine the order of reaction.

In this scenario, since the rate of reaction is directly proportional to the concentration of one reactant (let's say reactant A) and inversely proportional to the concentration of the other reactant (reactant B), we can write:

\(\text{Rate} = k[A]^1[B]^{-1} \)

Simplifying further, we get:

\(\text{Rate} = \frac{k[A]}{[B]} \)

Comparing this equation to the general form of a second-order reaction, we see that \(m = 1\) and \(n = -1\).

Therefore, the order of reaction is \(1 + (-1) = 0\).

Hence, the correct answer is option (1) 0.