Which of the following is the molecular formula of halous acid of chlorine?

The least active halogen with hydrogen is

Which of the following represents the correct order of acidic nature?

In the following reactions,products $(A)$ and $(B)$,respectively,are:
$6 NaOH + 3 Cl_{2} \xrightarrow{\text{hot and conc.}} (A) + \text{side products}$
$2 Ca(OH)_{2} + 2 Cl_{2} \xrightarrow{\text{dry}} (B) + \text{side products}$

Noble metals,like gold and platinum,are soluble in which of the following mixtures?

What is produced when bleaching powder reacts with dilute hydrochloric acid?