Given below are two statements :

Statement I : $$\alpha$$ and $$\beta$$ forms of sulphur can change reversibly between themselves with slow heating or slow cooling.

Statement II : At room temperature the stable crystalline form of sulphur is monoclinic sulphur.

In the light of the above statements, choose the correct answer from the options given below :

The correct statement about B₂H₆ is :

Al₂O₃ was leached with alkali to get X. The solution of X on passing of gas Y, forms Z. X, Y and Z respectively are :

The reaction of NO with N₂O₄ at 250 K gives :