Which of the following is the main component of Portland cement (besides lime)?

$A$ red coloured mixed oxide $(X)$ on treatment with conc. $HNO_3$ gives a compound $(Y).$ $(Y)$ with $HCl$ produces a chloride compound $(Z)$ which can also be produced by treating $(X)$ with conc. $HCl.$ Compounds $(X),$ $(Y),$ and $(Z)$ will be

Select the correct statement$(s)$.

Match the average fundamental compounds with their proper percentage present in Portland cement.

Compound	Percentage proportion
$1. CaO$	$d. 50-60\%$
$2. Al_2O_3$	$a. 5-10\%$
$3. SO_3$	$b. 1-3\%$

Which of the following does not dissolve in dil $H_2SO_4$?

Which of the following conduct electricity in the fused state?