Question

Carbon cannot reduce the oxides of sodium, magnesium, and aluminium to their respective metals. Why? Where these metals are placed in the reactivity series? How are these metals obtained from their ores? Take an example to explain the process of extraction along with chemical equations.

Answer 1

Hint: Elements and metals exist in nature in the form of ores. Ores are the impure form of the metals which need to be treated and thus pure metals are extracted from the treated ore. The level of purification needed for the extraction is dependent on the reactivity of the metals. The less reactive metals are easy to extract in comparison to metals that are highly reactive.

Complete step by step answer:
Elements in chemistry are arranged based on the reactivity of the elements. The more reactive elements are present higher in the reactivity series and the elements that are less reactive are present at the bottom.
According to the series of activities, carbon lies below all the elements that are present in the question namely, sodium, magnesium, and aluminium. This means that carbon is the least reactive among the lot.
From analyzing the reactivity series we see that carbon is less reactive than the rest of the elements and thus is unable to reduce the oxides of the given elements.
The extraction process of the metals which are more reactive is different from the elements that are less reactive. The metals like sodium, magnesium, and aluminium are extracted from their ores with the process of electrolytic reduction.
An example of one such process can be taken as the electrolysis of molten sodium chloride
$At\;{{ anode:\; C}}{{{l}}^ - } \to \dfrac{1}{2}C{l_2} + {e^ - }$
$A\;t{{ Cathode:\; N}}{{{a}}^ + } + {e^ - } \to N{a_{(s)}}$
So the overall reaction: $2NaCl \to 2N{a_{(s)}} + C{l_{2(g)}}$

Note: There are various methods for the initial treatment of the ore that is extracted from the rocks or other natural formations. It included crushing and pulverizing and treating with suitable processes.
The elements that are high in reactivity are separated by employing chemical processes in addition to the physical processes mentioned above.