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

Sodium oxalate on heating with conc. $H_2SO_4$ gives

Match the following columns:

Column-$I$	Column-$II$
$(i)$ Hydrogen peroxide	$(a)$ Used as air purifier in submarines
$(ii)$ Calcium sulphate hemihydrate	$(b)$ Used for water softening
$(iii)$ Potassium superoxide	$(c)$ Antiseptic
$(iv)$ Calgon	$(d)$ Plaster of Paris

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

Column $-I$	Column $-II$
$A$. Electrolysis of water produces	$1$. atomic reactor
$B$. Lithium aluminium hydride is used as	$2$. polar molecule
$C$. Hydrogen chloride is a	$3$. recombines on metal surface to generate high temperature
$D$. Heavy water is used in	$4$. reducing agent
$E$. Atomic hydrogen	$5$. hydrogen and oxygen

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?

Fill in the blanks:
$(1)$ Only $..........$ element of group $-6$ forms hydride.
$(2)$ $..........$ is used as a moderator in nuclear reactors.
$(3)$ The three-dimensional arrangement in ice occurs due to $..........$ bonding.
$(4)$ $..........$ method is used to obtain $H_2O_2$ from $2-$ethylanthraquinol.