Question

As an acid sulphur dioxide reacts with sodium hydroxide solution to form a salt called sodium sulphate Na2SO3 and water. Write a balanced chemical equation for the reaction (show state symbols)?

Answer 1

`SO_2 (g)+2NaOH_((s))->Na_2SO_3(s)+H_2O_((l))`

Explanation:

`SO_2 + NaOH->Na_2SO_3 + H_2O`

Now, a balanced equation of a reaction has equal atoms of each element on both sides. So we count the atoms each element.

• We have `1` atom of Sulphur on the one side (`SO_2`) and `1` on the other side (`Na_2SO_3`).

• We have `3` atoms of Oxygen on the one side (`SO_2` and `NaOH`), but `4` on the other side (`Na_2SO_3` and `H_2O`).

• We have `1` atom of Sodium (`NaOH`), but `2` on the other side (`Na_2SO_3`).

• We have `1` atom of Hydrogen (`NaOH`), but `2` on the other side (`H_2O`).

So to balance it:

`SO_2 (g)+2NaOH_((s))->Na_2SO_3(s)+H_2O_((l))`

`SO_2` is a gas.
`NaOH` is a powder, which means its solid.
`Na_2SO_3` is a salt in the form of a powder, which is solid.
`H_2O` is liquid, for obvious reasons.