Which of the following halogens is solid at room temperature?

Assertion $(A)$: The bond dissociation energy increases from $F_2$ to $Cl_2$ and then decreases to $I_2$.
Reason $(R)$: The low bond energy of fluorine is due to the repulsion between the lone pairs of electrons in two fluorine atoms.
The correct option among the following is

The sublimate formed during the process of sublimation of $Hg_2Cl_2$ with $NaCl$ is .........

An oxide of chlorine with water gives the strongest acid. The ratio of chlorine and oxygen in its formula is

Which one of the following statements is not correct?

Fluorine exhibits only $-1$ oxidation state whereas other halogens exhibit $+1, +3, +5$ and $+7$ oxidation states also. Explain.