How do you balance this chemical equation?

The given equation requires slight correction. The equation should be:

`NH_4^+ + HCl -> NH_4Cl`

Here, the ammonium ion (NH4+) reacts with hydrochloric acid and generates ammonium chloride. 

Let us check if the equation is well balanced. A balanced chemical equation contains an equal number of atoms of each species on both sides of the equation and the net charge on both the sides is equal is well. 

There is 1 atom of nitrogen on both sides. There is 1 atom of chlorine on each side. There are 5 hydrogen atoms on the reactant side, while only 4 atoms on the product side. Also, the reactant side has a net charge of +1, while the product side has a net charge of 0.

We can balance the hydrogen atom and charge by adding a proton (H+) to the product side. The resultant, well-balanced equation is:

`NH_4^+ + HCl -> NH_4Cl + H^+`

Hope this helps.