For the reaction C_2H_5Br_ (l) arrow C_2H_ 4(g) + HBr , r =...

The rate law is given as $r = K[\text{C}_2\text{H}_5\text{Br}]$.

The order of a reaction is the sum of the exponents of the concentration terms in the rate law. Since the exponent of $[\text{C}_2\text{H}_5\text{Br}]$ is $1$, the order of the reaction is $1$.

The molecularity of an elementary reaction is the number of reactant molecules taking part in the reaction. In the given reaction, only one molecule of $\text{C}_2\text{H}_5\text{Br}$ is reacting, so the molecularity is $1$.

Thus, the order and molecularity are $1$ and $1$ respectively.

Answer: $1, 1$