Railway wagon axles are made by heating iron rods embedded in charcoal powder. This process is known as:

Blister copper is refined by stirring molten impure metal with green logs of wood because such a wood liberates hydrocarbon gases (like $CH_4$) . This process $X$ is called . . . . . . . . . and the metal contains impurities of $Y$ is …….. .

Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason $R$

Assertion $A$ : The reduction of a metal oxide is easier if the metal formed is in liquid state than solid state.

Reason $R$ : The value of $\Delta G ^{\ominus}$ becomes more on negative side as entropy is higher in liquid state than solid state.

In the light of the above statements. Choose the most appropriate answer from the options given below.

Give the correct order of initials $T$ or $F$ for following statements. Use $T$ if statement is true and $F$ if it is false.

$(i)$  In Gold schmidt thermite process aluminium acts as a reducing agent .

$(ii)$  $Mg$ is extracted by electrolysis of aq. solution of $MgCl_2$

$(iii)$  Extraction of $Pb$ is possible by carbon reduction method

$(iv)$  Red Bauxite is purified by Serpeck's process

"Metals are usually not found as nitrates in their ores"

Out of the following two ( $a$ and $b$ ) reasons which is/are true for the above observation?

$(a)$ Metal nitrates are highly unstable

$(b)$ Metal nitrates are highly soluble in water