What products will be formed when calcium carbide reacts with nitrogen at $1000 \ ^oC$?

Which one of the following elemental forms is not present in the enamel of the teeth?

Which of the following statements is $NOT$ true?

Select the correct order of melting point:

$A$ solid element $Y$ conducts electricity and forms two types of chlorides: $YCl_n$ (a colorless volatile liquid) and $YCl_{n-2}$ (a colorless solid). To which group does element $Y$ belong?

Explain the following reactions:
$(a)$ Silicon is heated with methyl chloride at high temperature in the presence of copper;
$(b)$ Silicon dioxide is treated with hydrogen fluoride;
$(c)$ $CO$ is heated with $ZnO$;
$(d)$ Hydrated alumina is treated with aqueous $NaOH$ solution.