Potassium nitrate is made by adding potassium chloride to hydrogen nitrate in the presence of oxygen gas. Along with the potassium nitrate, chlorine and water are produced.

How would write the equation?

4KCl + 4HNO3 + O2 ==> 4KNO3 + 2Cl2 + 2H2O

To write the chemical equation for the reaction described, we need to understand the chemical formulas and balanced coefficients for each reactant and product involved.

The reactants mentioned are:
1. Potassium chloride (KCl)
2. Hydrogen nitrate (HNO3)
3. Oxygen gas (O2)

The products mentioned are:
1. Potassium nitrate (KNO3)
2. Chlorine gas (Cl2)
3. Water (H2O)

Now, let's write the balanced chemical equation step by step:

Step 1: Write the reactants on the left side of the equation.
KCl + HNO3 + O2

Step 2: Write the products on the right side of the equation.
KNO3 + Cl2 + H2O

Step 3: Balance the equation by adding coefficients to make sure the number of atoms on both sides is equal.

The balanced equation is:
2KCl + 2HNO3 + O2 → 2KNO3 + Cl2 + H2O

In this balanced equation, the coefficients before each compound indicate the number of molecules (or formula units) of each substance involved in the reaction.