Which of the following elements has the lowest melting point?

Which of the following compounds of lead is used in the match industry?

When $MnO_2$ and $H_2SO_4$ are added to a salt $(A)$,the greenish yellow gas liberated indicates that salt $(A)$ is:

Correct statements among $(i)$ to $(iv)$ regarding silicones are:
$(i)$ they are polymers with hydrophobic character
$(ii)$ they are biocompatible
$(iii)$ in general,they have high thermal stability and low dielectric strength
$(iv)$ usually they are resistant to oxidation and used as greases.

The silicate anion in the mineral kinoite is a chain of three $SiO_4$ tetrahedra that share corners with adjacent tetrahedra. The mineral also contains $Ca^{2+}$ ions,$Cu^{2+}$ ions,and water molecules in a $1 : 1 : 1$ ratio. The mineral is represented as:

Which of the following properties is $NOT$ exhibited by carbon?