# Which two elements are not balanced in this equation? Na_2S + ZnCl_2 -> NaCl + ZnS

May 6, 2017

#### Answer:

The sodium and the chlorine atoms..........

#### Explanation:

$\text{Stoichiometry}$ requires (i) that mass be balanced, and (ii) that charge be balanced........

We can put a check mark next to $\left(i i\right)$, but clearly for $\left(i\right)$ there are 2 natrium reactants, and 1 natrium product, and 2 chlorine reactants, and 1 chlorine products:

And thus the stoichiometric equation is...........:

$N {a}_{2} S \left(a q\right) + Z n C {l}_{2} \left(a q\right) \rightarrow Z n S \left(s\right) \downarrow + 2 N a C l \left(a q\right)$.

Are charge and mass balanced here? Don't trust my 'rithmetic!