The correct formula of hypo is

Give a brief account of the abundance of alkali metals and alkaline earth metals in the Earth's crust.

Which of the anhydrous salts,when it comes in contact with water,turns blue?

Match the following items in Column-$I$ with the corresponding items in Column-$II$.

Column-$I$	Column-$II$
$I$. $Na_2CO_3 \cdot 10H_2O$	$A$. Portland cement ingredient
$II$. $Mg(HCO_3)_2$	$B$. Castner-Kellner process
$III$. $NaOH$	$C$. Solvay process
$IV$. $Ca_3Al_2O_6$	$D$. Temporary hardness

Consider three metal chlorides $x$, $y$ and $z$, where $x$ is water soluble at room temperature, $y$ is sparingly soluble in water at room temperature and $z$ is soluble in hot water. $x$, $y$ and $z$ are respectively:

Tempered steel is