Question

what is the missing coefficient to make a balanced equation? 2na + ?cl₂ → nacl

Explanation:

Step1: Count sodium atoms

On the left - hand side, we have 2 Na atoms.

Step2: Count chlorine atoms

On the left - hand side, if we assume the coefficient of $Cl_2$ is $x$, we have $2x$ chlorine atoms. On the right - hand side, if the coefficient of $NaCl$ is $y$, we have $y$ sodium and $y$ chlorine atoms. Since we have 2 Na on the left, $y = 2$ to balance sodium. Then for chlorine, since we have 2 chlorine atoms in $Cl_2$, and we need 2 chlorine atoms on the right in $2NaCl$, the coefficient of $Cl_2$ is 1.

Answer:

The coefficient of $Cl_2$ is 1 and the coefficient of $NaCl$ is 2.