To balance the chemical equation Zn + HCl → ZnCl₂ + H₂, we need to ensure that there are equal numbers of each type of atom on both sides of the equation.
1. **Count the Atoms**: Initially, we have:
- Zn: 1 on the left, 1 on the right
- H: 1 on the left (from HCl), 2 on the right (from H₂)
- Cl: 1 on the left (from HCl), 2 on the right (from ZnCl₂)
2. **Balancing Chlorine**: To balance the chlorine atoms, we see that there are 2 chloride ions in ZnCl₂. Therefore, we need to place a coefficient of 2 in front of HCl:
Zn + 2 HCl → ZnCl₂ + H₂
3. **Recount the Atoms**: Now, the count is:
- Zn: 1 on both sides
- H: 2 on the left (from 2 HCl), 2 on the right (from H₂)
- Cl: 2 on the left (from 2 HCl), 2 on the right (from ZnCl₂)
4. **Final Check**: All atoms are balanced: 1 Zn, 2 H, and 2 Cl on both sides.
Thus, the balanced equation is:
Zn + 2 HCl → ZnCl₂ + H₂