Question

When ferrous sulphate $\left({\text{FeSO}}_4\right)$ solution combines with sodium hydroxide $\text{(NaOH)}$, the chemical change is identified by the .

• A. formation of gas
• B. formation of ppt
• C. absoprtion of heat

Answer 1

The correct option is B formation of ppt

When sodium hydroxide is added to ferrous sulphate solution, a dirty green coloured precipitate (ppt) of ferrous hydroxide, ${\text{Fe(OH)}}_2$, is formed.

This confirms that a chemical change, i.e., a chemical reaction has occurred.
${\mathrm{FeSO}}_4\left(\mathrm{aq}\right)+2\mathrm{NaOH}\left(\mathrm{aq}\right)\to {\mathrm{Na}}_2{\mathrm{SO}}_4\left(\mathrm{aq}\right)+\mathrm{Fe}(\mathrm{OH}{)}_2\left(s\right)$