4. Chemical bonding and molecular structure — Chemistry STD 11 Science — Question

$(A)$ the reaction of $Al _2 O _3$ with coke ($C$) at a temperature $>2500^{\circ} C$.

$(B)$ the neutralization of aluminate solution by passing $CO _2$ gas to precipitate hydrated alumina $\left( Al _2 O _3 .3 H _2 O \right)$

$(C)$ the dissolution of $Al _2 O _3$ in hot aqueous $NaOH$.

$(D)$ the electrolysis of $Al _2 O _3$ mixed with $Na _3 AlF _6$ to give $Al$ and $CO _2$.

${K_p} = 8 \times {10^{ - 2}}$$C{O_{2(g)}} + {C_{(s)}} \to 2C{O_{(g)}}$ ; ${K_p} = 2$

$CaC{{O}_{3(s)}}\xrightarrow{\Delta }Ca{{O}_{(s)}}+C{{O}_{2}}\uparrow $;  ${{K}_{p}}=8\times {{10}^{-2}}$