The most abundant element on the earth's crust is

Sulphuryl chloride $(SO_{2}Cl_{2})$ reacts with white phosphorus $(P_{4})$ to give:

In the contact process for the production of $H_2SO_4$,which catalyst is required to convert $SO_2$ into $SO_3$?

$H_2S$ is more acidic than $H_2O$,due to

Below are two statements. One is labeled as Assertion $(A)$ and the other as Reason $(R):$
Assertion $(A):$ $H_2Te$ is more acidic than $H_2S$.
Reason $(R):$ The bond dissociation enthalpy of $H_2Te$ is less than that of $H_2S$.
In the context of the above statements,choose the correct answer from the following options:

In the case of hydrides of the oxygen family,which of the following physical properties changes regularly on moving down the group?