Which of the following is correctly matched?

Refractory materials are generally used in furnaces because

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 Goldschmidt thermite process,aluminium acts as a reducing agent.
$(ii)$ $Mg$ is extracted by electrolysis of aqueous solution of $MgCl_2$.
$(iii)$ Extraction of $Pb$ is possible by carbon reduction method.
$(iv)$ Red Bauxite is purified by Serpeck's process.

Among the following compounds,the number of those present in copper matte is $......$
$A.$ $CuCO_3$
$B.$ $Cu_2S$
$C.$ $Cu_2O$
$D.$ $FeO$

In aluminium extraction by the Bayer process, alumina is extracted from bauxite by sodium hydroxide at high temperature and pressure: $Al_2O_{3(s)} + 2 OH^-_{(aq)} + 3 H_2O_{(l)} \rightarrow 2 [Al(OH)_4]^-_{(aq)}$. Solid impurities such as $Fe_2O_3$ and $SiO_2$ are removed and then $[Al(OH)_4]^-$ is reprecipitated: $2 [Al(OH)_4]^-_{(aq)} \rightarrow Al_2O_3 \cdot 3 H_2O_{(s)} + 2 OH^-_{(aq)}$. In the industrial world:

Solder is an alloy of