Which one of the following compounds of Group-$14$ elements is not known?

Explain the following:
$(1)$ $Tl(NO_3)_3$ acts as an oxidizing agent.
$(2)$ Carbon shows catenation property but lead does not.

Carbon can form $p\pi-p\pi$ bond with which kind of elements?

The element with atomic number $Z = 114$ has been discovered recently. It will belong to which of the following family/group and electronic configuration?

The sides of a matchbox have a coating of:

$A$ red solid is insoluble in water,but it becomes soluble if a small amount of $KI$ is added to the water. If this red solid is heated in a test tube,it produces a violet-colored vapor and some metallic droplets are observed on the cooler parts of the test tube. This red solid is........