Write the formula for green vitriol?

• Sulphates and its related metal compounds are termed as vitriols.
• Different metals when associated with Sulphates form vitriols of different colors, for example Iron form green vitriol, Zinc gives white vitriol etc.
• Green vitriol is formed due to the Ferrous metal associated with the Sulphate.
• The reaction for the preparation is shown below.
  $$\begin{gathered} \mathrm{FeS}\left(\mathrm{s}\right)+{\mathrm{H}}_2{\mathrm{SO}}_4\left(aq\right)\to {\mathrm{FeSO}}_4\left(\mathrm{aq}\right)+{\mathrm{H}}_2\mathrm{S}\left(\mathrm{g}\right) \\ \mathrm{Iron}\mathrm{Sulphuric}\mathrm{Iron}\mathrm{Hydrogen} \\ \mathrm{sulphide}\mathrm{acid}\mathrm{sulphate}\mathrm{sulphide} \end{gathered}$$
• Green vitriol has seven molecules of water along with the Ferrous sulfate, forming a blue-green compound.
• Thus, the chemical formula of green vitriol is Ferrous sulphate heptahydrate ${\mathbf{FeSO}}_{\mathbf{4}}\mathbf{.}\mathbf{7}{\mathbf{H}}_{\mathbf{2}}\mathbf{O}$.