Glass reacts with $HF$ to produce

When a mixture of solid $NaCl$ and solid $K_2Cr_2O_7$ is heated with concentrated $H_2SO_4$,orange-red vapours are evolved. These vapours are of which compound?

Which of the following halogens has the highest bond dissociation energy?

Sulphur dioxide on reaction with chlorine in the presence of charcoal gives compound $(A)$. This on reaction with white phosphorus gives $SO_2$ and compound $(B)$. The correct statement about '$B$' is

$A$ mixture of concentrated $HCl$ and $HNO_3$ in a $3:1$ ratio contains ..........

Silver nitrate is supplied in coloured bottles because it is