The setting time of cement is increased by adding which of the following?

Which of the following are amphoteric oxides?

Which of the following has the highest electrode potential?

$A$ compound $x$ on heating gives a colourless gas. The residue is dissolved in water to obtain $y$. Excess $CO_2$ is bubbled through the aqueous solution of $y$ and $z$ is formed. $z$ on gentle heating gives back $x$. The compound $x$ is:

Match List-$I$ with List-$II$.

List-$I$	List-$II$
$a$. $Ca(OCl)_2$	$i$. Antacid
$b$. $CaSO_4 \cdot \frac{1}{2} H_2O$	$ii$. Cement
$c$. $CaO$	$iii$. Bleach
$d$. $CaCO_3$	$iv$. Plaster of Paris

Choose the most appropriate answer from the options given below:

Which property of alkaline earth metals increases with their atomic number?