Jee Main
D And F Block Elements
JEE Main 2026 (Online) 5th April Evening Shift
MCQ+4 / -12026
A paper dipped in a dil. $\mathrm{H}_2 \mathrm{SO}_4$ solution of ' $X$ ' upon treatment with $\mathrm{SO}_2$ gas turns into green. The compound ' $X$ ' is :
