Match the following and identify the correct option.

$a. CO_{(g)} + H_{2(g)}$	$i. Mg(HCO_3)_2 + Ca(HCO_3)_2$
$b. \text{Temporary hardness of water}$	$ii. \text{An electron deficient hydride}$
$c. B_2H_6$	$iii. \text{Synthesis gas}$
$d. H_2O_2$	$iv. \text{Non-planar structure}$

Oxalic acid reacts with concentrated $H_2SO_4$ to produce a mixture of two gases. When this mixture is passed through caustic potash,one of the gases is absorbed. Which substance is formed by the absorption of the gas in caustic potash?

Match the correct option from Column $-A$ and Column $-B$.

Column $-A$	Column $-B$
$(1).$ Calgon	$(a).$ $D_2O$
$(2).$ Perhydrol	$(b).$ Zeolite
$(3).$ Heavy water	$(c).$ Sodium hexametaphosphate
$(4).$ Aluminosilicate	$(d).$ Commercial name of Hydrogen peroxide

Consider the following statements:
$I$. Atomic hydrogen is obtained by passing an electric arc through hydrogen gas.
$II$. Hydrogen gas does not reduce heated aluminum oxide.
$III$. Finely divided palladium absorbs a large volume of hydrogen gas.
$IV$. Pure nascent hydrogen is obtained by the reaction of $Na$ with $C_2H_5OH$.
Which of the above statements are correct?

Match the items in Column-$I$ with the relevant item in Column-$II$.

Column-$I$	Column-$II$
$A$. Hydrogen peroxide is used as a	$1$. zeolite
$B$. Used in Calgon method	$2$. perhydrol
$C$. Permanent hardness of hard water is removed by	$3$. sodium hexametaphosphate
	$4$. propellant

The order $H_2O < H_2O_2$ is correct for which of the following properties?