The compound that is used in smoke screens is

The stability of dihalides of $Si, Ge, Sn$ and $Pb$ increases in the order:

Evaluate the following statements related to group $14$ elements for their correctness.
$(A)$ Covalent radius decreases down the group from $C$ to $Pb$ in a regular manner.
$(B)$ Electronegativity decreases from $C$ to $Pb$ down the group gradually.
$(C)$ Maximum covalence of $C$ is $4$ whereas other elements can expand their covalence due to presence of $d$ orbitals.
$(D)$ Heavier elements do not form $p\pi-p\pi$ bonds.
$(E)$ Carbon can exhibit negative oxidation states.
Choose the correct answer from the options given below:

Oxygen gas is not produced from the following decomposition reaction:

The products formed when gaseous $HCl$ is passed into an aqueous $Na_2SO_3$ solution are:

Which among the following does not undergo hydrolysis?