$A$ major constituent of Portland cement,except lime,is:

Phosphorus has the oxidation state of $+3$ in

Which of the following is not correct corresponding to the chemistry of group $14$ elements?

$[SiF_6]^{2-}$ is known whereas $[SiCl_6]^{2-}$ is not. Give possible reasons.

Which of the following oxides is amphoteric?

For correct statement use $T$ and for incorrect use $F$:
$(A)$ Hydrolysis of Marshall's acid gives $H_2SO_4$ and $H_2O_2$ as final products.
$(B)$ In $SCNSiH_3$ structure,the geometry around $N$ is bent.
$(C)$ The basic unit for silicates is $SiO_4^{4-}$.
$(D)$ $NH_4Cl + NaOH \to NH_3 \uparrow$.