Aluminium is stable in air and water in spite of the fact that it is reactive metal. The…

Aluminium is stable in air and water in spite of the fact that it is reactive metal. The reason is that a thin film of its oxide is formed on its surface which it passive for further attack. The layer is so useful that in industry, it is purposely deposited by an electrolytic process called anodising
Reaction of aluminium with oxygen is highly exothermic and is called thermite reaction.
\(\text { ÄAIl(v) } \mathrm{H}_{2}^{3} \mathrm{O}_{2} \mathrm{O}(\mathrm{~g}) \rightarrow \mathrm{Al}_{2} \mathrm{O}_{3}(\mathrm{~s}) \text {; }\) 
Thermite reaction finds applications in the metallurgical extraction of many metals from their oxides and for welding of metals. The drawback is that to start the reaction, high temperature is required for which an ignition mixture is used.
Which one of the following metals cannot be extracted by using Al as a reducing agent?