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# A metal A, which is used in the thermite process, when heated with oxygen gives an oxide B, which is amphoteric in nature. Identify A and B. Write down the reactions of oxide B with HCl and NaOH

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## Step 1: The metal A which is used in the Thermite process, when heated with Oxygen gives an Oxide B, which is amphoteric in nature:The metal A is Aluminium.When aluminum reacts with Oxygen, it forms an Aluminum oxide$\left({\mathrm{Al}}_{2}{\mathrm{O}}_{3}\right)$ which is an amphoteric oxide i.e. it behaves as both acidic as well as basic oxide.The chemical reaction can be depicted as: $4\mathrm{Al}\left(\mathrm{s}\right)+3{\mathrm{O}}_{2}\left(\mathrm{g}\right)\to 2{\mathrm{Al}}_{2}{\mathrm{O}}_{3}\left(\mathrm{s}\right)$Step 2: The reaction of Aluminium oxide with Hydrochloric acid:When Aluminium oxide$\left({\mathrm{Al}}_{2}{\mathrm{O}}_{3}\right)$ reacts with Hydrochloric acid$\left(\mathrm{HCl}\right)$, it forms a salt of Aluminium which is Aluminium chloride$\left({\mathrm{AlCl}}_{3}\right)$ and water.The chemical reaction can be depicted as: ${\mathrm{Al}}_{2}{\mathrm{O}}_{3}\left(\mathrm{s}\right)+6\mathrm{HCl}\left(\mathrm{aq}\right)\to 2{\mathrm{AlCl}}_{3}\left(\mathrm{s}\right)+3{\mathrm{H}}_{2}\mathrm{O}\left(\mathrm{l}\right)$Step 3: The reaction of Aluminum oxide with Sodium hydroxide:When Aluminum oxide$\left({\mathrm{Al}}_{2}{\mathrm{O}}_{3}\right)$ reacts with Sodium hydroxide$\left(\mathrm{NaOH}\right)$, it forms Sodium aluminate$\left({\mathrm{NaAlO}}_{2}\right)$ and water.The chemical reaction can be depicted as: ${\mathrm{Al}}_{2}{\mathrm{O}}_{3}\left(\mathrm{s}\right)+2\mathrm{NaOH}\left(\mathrm{aq}\right)\to 2{\mathrm{NaAlO}}_{2}\left(\mathrm{s}\right)+{\mathrm{H}}_{2}\mathrm{O}\left(\mathrm{l}\right)$Thus, A and B are Aluminum and Aluminium oxide respectively.

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