Question

Write balanced equation for the following reaction:

(b) Copper sulfate solution is added to sodium hydroxide solution.

Answer 1

Reaction summary:

When copper sulfate $\left({\mathrm{CuSO}}_4\right)$ and sodium hydroxide $\left(\mathrm{NaOH}\right)$ reacts, a blue colored precipitate of copper hydroxide $\left(\mathrm{Cu}{\left(\mathrm{OH}\right)}_2\right)$ is formed.

Skeleton reaction:

${\mathrm{CuSO}}_4\left(\mathrm{aq}\right)+\mathrm{NaOH}\left(\mathrm{aq}\right)\to \mathrm{Cu}{\left(\mathrm{OH}\right)}_2\downarrow +{\mathrm{Na}}_2{\mathrm{SO}}_4\left(\mathrm{aq}\right)$

Step 1:

• To balance the chemical equation, first make a list of the number of atoms of different types that are present on both sides (reactant and product side) of the chemical equation.

${\mathrm{CuSO}}_4\left(\mathrm{aq}\right)+\mathrm{NaOH}\left(\mathrm{aq}\right)\to \mathrm{Cu}{\left(\mathrm{OH}\right)}_2\downarrow +{\mathrm{Na}}_2{\mathrm{SO}}_4\left(\mathrm{aq}\right)$

Let's determine the number of atoms for each element.

Element Reactants Products

Copper 1 1

Oxygen 5 6

Sodium 1 2

Sulfur 1 1

Hydrogen 1 2

Step 2:

• Multiply the $\left(\mathrm{NaOH}\right)$ by 2 on the reactant side, because there are 2 atoms of sodium on the product side.

Therefore, the equation becomes:

${\mathrm{CuSO}}_4\left(\mathrm{aq}\right)+2\mathrm{NaOH}\left(\mathrm{aq}\right)\to \mathrm{Cu}{\left(\mathrm{OH}\right)}_2\downarrow +{\mathrm{Na}}_2{\mathrm{SO}}_4\left(\mathrm{aq}\right)$

Element Reactants Products

Copper 1 1

Oxygen 6 6

Sodium 2 2

Sulfur 1 1

Hydrogen 2 2

The reactants and products in this chemical equation have an equal number of different types of atoms.

Balanced chemical reaction:

${\mathrm{CuSO}}_4\left(\mathrm{aq}\right)+2\mathrm{NaOH}\left(\mathrm{aq}\right)\to \mathrm{Cu}{\left(\mathrm{OH}\right)}_2\downarrow +{\mathrm{Na}}_2{\mathrm{SO}}_4\left(\mathrm{aq}\right)$