Three parts of $conc. HCl$ and one part of $conc. HNO_3$ are mixed to form aqua regia. It is used to dissolve:

$MnO_{2} + HCl \xrightarrow{\Delta} A_{(g)}$
$A_{(g)} + F_{2} (\text{excess}) \rightarrow B_{(g)}$
$B_{(l)} + U_{(s)} \rightarrow C_{(g)} + D_{(g)}$
The gases $A$,$B$,$C$ and $D$ are respectively

Which of the following is the only existing oxoacid of fluorine?

$Cl_2$ gas is dried over which of the following?

Arrange the following in the order of property indicated for each set:
$(i)$ $F_{2}, Cl_{2}, Br_{2}, I_{2}$ - increasing bond dissociation enthalpy.
$(ii)$ $HF, HCl, HBr, HI$ - increasing acid strength.
$(iii)$ $NH_{3}, PH_{3}, AsH_{3}, SbH_{3}, BiH_{3}$ - increasing base strength.

The correct order of acidic strength is