It seems like you're referring to a chemical reaction involving nitric acid (HNO₃) and zinc (Zn) with hydrogen gas (H₂). However, the formula or the complete equation is not provided here.
To determine which coefficient needs to be changed, we typically balance a chemical equation to ensure that the number of atoms for each element is the same on both sides of the equation.
If you have a specific unbalanced equation in mind, you could provide that, and I could help you identify which coefficient needs to be adjusted. Alternatively, if you give me more context or details about the reaction you are referring to, I could assist you in balancing the equation and pinpointing the specific coefficients that may need to be changed.