(a)
Green vitriol is formed by oxidation of iron pyrite in presence of air and water.
$2{FeS}_{2} + 2H_{2}O + 7O_{2}\ \longrightarrow 2{FeSO}_{4} + 2H_{2}{SO}_{4}$
pyrites green vitriol
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.