The gas evolved on heating $CaF_2$ and $SiO_2$ with concentrated $H_2SO_4$,on hydrolysis gives a white gelatinous precipitate. The precipitate is

Which of the following statements regarding halogens is correct?

In the manufacture of bromine from sea water,the mother liquor containing bromides is treated with:

Which of the following hydrogen halide is most volatile?

Given below are two statements: one is labelled as Assertion $(A)$ and the other is labelled as Reason $(R).$
Assertion $(A):$ $ICl$ is more reactive than $I_{2}.$
Reason $(R):$ $I-Cl$ bond is weaker than $I-I$ bond.
In the light of the above statements,choose the most appropriate answer from the options given below:

When treated with conc. $HCl$,$MnO_2$ yields a gas $(X)$ which further reacts with $Ca(OH)_2$ to generate a white solid $(Y)$. The solid $Y$ reacts with dil. $HCl$ to produce the same gas $X$. The solid $Y$ is