Which of the following is the correct order of reactivity of halogens with alkali?

In the following reaction,identify the nature of the product formed by the complete hydrolysis of the underlined atom at $R.T.$:
$\underline{I}OF_5 + 2H_2O \longrightarrow HIO_4 + 5HF$

Which of the following acids is the weakest?

Which gas has been used since ancient times to remove lignin from wood?

The correct statement$(s)$ about the oxoacids,$HClO_4$ and $HClO$,is(are):
$[A]$ $HClO_4$ is more acidic than $HClO$ because of the resonance stabilization of its anion.
$[B]$ $HClO_4$ is formed in the reaction between $Cl_2$ and $H_2O$.
$[C]$ The central atom in both $HClO_4$ and $HClO$ is $sp^3$ hybridized.
$[D]$ The conjugate base of $HClO_4$ is a weaker base than $H_2O$.

What is obtained upon strong heating of $H_5IO_6$?