The most efficient agent for the absorption of $SO_3$ is

Elements of Group $16$ generally show lower value of first ionisation enthalpy compared to the corresponding periods of Group $15$. Why?

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 statements is false about oxygen and sulphur?

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:

Observe the following statements :
$a$. The thermal stability of hydrides of group $16$ elements follows the order :
$H_2O > H_2S > H_2Se > H_2Te$
$b$. Acidic nature of hydrides of group $16$ elements follows the order :
$H_2O < H_2S < H_2Se < H_2Te$
$c$. The reducing nature of $H_2S$,$H_2Se$ and $H_2Te$ follows the order :
$H_2S < H_2Se < H_2Te$
The correct statements are: