In which of the following reactions,$H_2$ is liberated?
$i$. $Al_{(s)} + HCl_{(aq)} \rightarrow$
$ii$. $Al_{(s)} + NaOH_{(aq)} \rightarrow$
$iii$. $B_2H_{6(g)} + H_2O_{(l)} \rightarrow$
$iv$. $F_{2(g)} + H_2O_{(l)} \rightarrow$

When oxalic acid reacts with conc. $H_2SO_4$,two gases produced are of neutral and acidic in nature respectively. Potassium hydroxide absorbs one of the two gases. The product formed during this absorption and the gas which gets absorbed are respectively

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 following and identify the correct option.

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

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

Correct order of boiling point $(BP)$ is: