Which of the following gases is insoluble in water?

Reaction between $X$ and $Y$ forms compound $Z$. $X$ loses an electron and $Y$ gains an electron. Which of the following properties is not shown by $Z$?

Which of the following methods is used for the concentration of ore?

What is the molecular formula of calcium silicate (slag)?

$A$ metal that exists as a liquid at room temperature is obtained by heating its sulphide in the presence of air. Identify the metal and its ore and give the reaction involved.

Name two metals in each of the following cases:
$(i)$ Metals that are stored in kerosene.
$(ii)$ Metals that are alloyed with iron to make stainless steel.
$(iii)$ Metals which are highly malleable and ductile.