Answer : In the reaction of Ca +
![F _(2)](https://img.qammunity.org/2019/formulas/chemistry/high-school/g6zqbkz0h832i7f30exheksjqjnnro7xik.png)
--->Ca
![F _(2)](https://img.qammunity.org/2019/formulas/chemistry/high-school/g6zqbkz0h832i7f30exheksjqjnnro7xik.png)
, the coefficient of Ca and
![F _(2)](https://img.qammunity.org/2019/formulas/chemistry/high-school/g6zqbkz0h832i7f30exheksjqjnnro7xik.png)
will be the same which will be 1.
Explanation : As per the rules of writing a chemical equation and balancing it properly, the number of elements in reactants side should be equal to the number of elements generated in product side. Hence when we use 1 molecule of Ca and one molecule of
![F _(2)](https://img.qammunity.org/2019/formulas/chemistry/high-school/g6zqbkz0h832i7f30exheksjqjnnro7xik.png)
then it generates 1 molecule of Ca
![F _(2)](https://img.qammunity.org/2019/formulas/chemistry/high-school/g6zqbkz0h832i7f30exheksjqjnnro7xik.png)
.