Which of the following is least hydrolysed?

$A$ metal $M$ readily gives $MSO_4$, which is soluble in water. It forms its oxide $MO$ which is amphoteric. It forms an insoluble hydroxide $M(OH)_2$, which is soluble in $NaOH$ solution. The $M$ is

Explain the anomalous behavior of beryllium.

Solubility of sulphates of group $2$ elements decreases down the group due to

For a good quality cement,the ratio of silica to alumina should be in the range of:

When water is added to compound $(A)$ of calcium,a solution of compound $(B)$ is formed. When carbon dioxide is passed into the solution,it turns milky due to the formation of compound $(C)$. If excess of carbon dioxide is passed into the solution,the milkiness disappears due to the formation of compound $(D)$. Identify the compounds $A$,$B$,$C$,and $D$. Explain why the milkiness disappears in the last step.