In this reaction copper sulphate reacts with sodium hydroxide to from copper hydroxide and sodium sulphate. This can be written in the form of a word equation as :
Copper sulphate + sodium hydroxide `to` Copper hydroxide + sodium sulphate
`{:(Now",","Formula of copper sulphate is"CuSO_(4)),(,"Formula of sodium hydroxide is"NaOH),(,"Formula of copper hydroxide is"Cu(OH)_(2)),(And",","Formula of sodium sulphate is" Na_(2)SO_(4)):}`
Putting these formulae in the above word-equation, we get:
`" "CuSO_(4)+NaOHtoCu(OH)_(2)+Na_(2)SO_(4)`
Let us count the number of various types of atoms in reactants as well as products.
`{:(,"In reactants","In products"),("No . of Cu atoms:",1,1),("No . of S atoms:",1,1),("No . of O atoms:",5,6),("No . of Na atoms:",1,2),("No . of H atoms:",1,2):}`
We find that the number of copper atoms and sulphur atoms is equal on both the sides (1 each), but the number of oxygen atoms, sodium atoms and hydrogen atoms is not equal. Let us take the oxygen atoms first. There are 5 oxygen atoms on left side but 6 oxygen atoms on the left side but 6 oxygen atoms on the right side. To have 6 oxygen atoms on the left side, we multiple NaOH by 2 and write 2NaOH. Thus,
`" "CuSO_(4)+2NaOHto Cu(OH)_(2)+Na_(2)SO_(4)`
Let us count the number of various types of atoms on both the sides once again.
`{:(,"In reactants","In products"),("No . of Cu atoms:",1,1),("No . of S atoms:",1,1),("No . of O atoms:",6,6),("No . of Na atoms:",2,2),("No . of H atoms:",1,2):}`
This equation contains an equal number of various types of atoms on both the sides, so this is a balanced equation.
Copper sulphate is an squeous solution, so we write `CuSO_(4)` (aq)
Sodium hydroxide is also an aqueous solution, we write NaOH (aq)
Copper hydroxide is formed as a precipitate (solid), so we write `Cu(OH)_(2)` (s)
Sodium sulphate is in solution, so we write `Na_(2)SO_(4)` (aq)
The above equation can now be written as :
`CuSO_(4)(aq)+2NaOH(aq)toCu(OH)_(2)(s)+Na_(2)SO_(4)(aq)`
