Question

Write a net ionic equation for the reaction that occurs when manganese(II) sulfide and excess hydrochloric acid (aq) are combined.

Answer 1

Manganese(II) Sulfide (solid) when added to Hydrochloric acid (aqueous) produces Manganese(II) Chloride (solid) and Hydrogen Sulfide (gas).

MnS _(s) + HCl _(aq) MnCl_{2 (aq)} + H₂S _(g)

The net ionic equation is written by the following steps:

1. Write the balanced molecular equation.

Since 2 Chlorine and 2 Hydrogen atoms are present in the right side of the equation, we'll make the coefficient of HCl as 2. The rest of the equations looks balanced now.

MnS _(s) + 2HCl _(aq) MnCl_{2 (aq)} + H₂S _(g)

2. Write the state for each substance (solid, liquid, gaseous or aqueous)

We need to be aware of the states of each substance as when we write the net ionic equations then only the aqueous substance breaks into its ions while the rest remain as it is.

3. Break soluble compounds into ions. This is known as the complete ionic equation.

Now, only the aqueous substance will break down into ions while the solid and gaseous substance will remain as it is.

MnS _(s) + 2 H⁺_(aq) + 2 Cl^-_(aq) Mn²⁺_(aq) + 2 Cl^-_(aq) + H₂S _(g)

4. Cancel out spectator ions that are present on both sides of the equation.

Now notice that 2 Cl^-_(aq) is present on both sides of the equation. These type of ions that are present on both the sides of a equation are called Spectator ions as they don't participate in the reaction so we can just cross out or cancel them from the equation.

5. Write the remaining substances as the net ionic equation.

MnS _(s) + 2 H⁺_(aq) Mn²⁺_(aq) + H₂S _(g)

This is how you write a net ionic equation.