To find the mole ratio of [tex]\( \text{Cl}_2 \)[/tex] to [tex]\( \text{Br}_2 \)[/tex] in the given reaction, follow these steps:
1. Write the balanced chemical equation:
[tex]\[
\text{Cl}_2 + 2 \text{NaBr} \rightarrow 2 \text{NaCl} + \text{Br}_2
\][/tex]
2. Identify the coefficients of the substances involved:
- The coefficient for [tex]\( \text{Cl}_2 \)[/tex] is 1.
- The coefficient for [tex]\( \text{Br}_2 \)[/tex] is 1.
3. Determine the mole ratio:
The mole ratio is given by the coefficients of [tex]\( \text{Cl}_2 \)[/tex] and [tex]\( \text{Br}_2 \)[/tex]:
[tex]\[
\frac{\text{Coefficient of } \text{Cl}_2}{\text{Coefficient of } \text{Br}_2} = \frac{1}{1}
\][/tex]
Thus, the mole ratio of [tex]\( \text{Cl}_2 \)[/tex] to [tex]\( \text{Br}_2 \)[/tex] is [tex]\( 1 : 1 \)[/tex].
4. Select the correct option:
Option A corresponds to the mole ratio [tex]\( 1 : 1 \)[/tex].
Therefore, the correct answer is:
[tex]\[
\boxed{1:1}
\][/tex]
So, the correct option is:
[tex]\[
\boxed{\text{A}}
\][/tex]
