Lanthanoids (Ln) when heated with S, generally give.........

$Ln_2S_3$

The correct answer is Option (2) → $Ln_2S_3$

Lanthanoids (Ln) generally exhibit a +3 oxidation state. When they react with sulfur (S), they form sesquisulfides with the formula:

$2 \text{Ln} + 3 \text{S} \rightarrow \text{Ln}_2\text{S}_3$

So the correct answer is: Ln₂S₃