When a colorless gas is passed through bromine water and it causes decolorization,which gas is it?

What is the atomicity of sulfur in rhombic sulfur?

Given below are two statements:
Statement $I$: The boiling points of the following hydrides of group $16$ elements increase in the order: $H_2O < H_2S < H_2Se < H_2Te$.
Statement $II$: The boiling points of these hydrides increase with an increase in molar mass.
In the light of the above statements,choose the most appropriate answer from the options given below:

Which of the following molecules exhibits the lowest thermal stability?

Among the hydrides of group $16$ elements, the hydride $X$ has the lowest boiling point and the hydride $Y$ has the highest boiling point. $X$ and $Y$ respectively are:

Discuss the anomalous behaviour of oxygen.