Chemistry - Complete s-block Question with Solution | TestHub

For a good quality cement, the ratio of Lime (CaO) to the total of the oxides of silicon $\left({\mathrm{SiO}}_2\right)$, Aluminium $\left({\mathrm{Al}}_2{\mathrm{O}}_3\right)$ and iron $\left({\mathrm{Fe}}_2{\mathrm{O}}_3\right)$ should be as close as possible to $\_\_\_\_$