Which of the following oxidation states are exhibited by iodine?

Among the following oxoacids,the correct decreasing order of acid strength is:

The correct order of acidic strength of oxy-acids of chlorine is

Which of the following halogens does not exhibit a positive oxidation state in its compounds?

Aluminium trifluoride is insoluble in anhydrous $HF$ but dissolves on addition of $NaF$. Aluminium trifluoride precipitates out of the resulting solution when gaseous $BF_3$ is bubbled through. Give reasons.

Consider the following statements about the oxides of halogens:
$A$. At room temperature, $OF_2$ is thermally stable.
$B$. Order of stability of oxides of halogens is $I > Br > Cl$.
$C$. $I_2O_5$ is used in the estimation of $CO$.
$D$. $ClO_2$ is used as a bleaching agent.
The correct statements are: