Question

In Halls process,

• A. bauxite ore is fused with $ NaOH $
• B. ammonia is prepared
• C. $ A{{l}_{2}}{{O}_{3}}\cdot 2{{H}_{2}}O $ is fused with $ NaHC{{O}_{3}} $
• D. bauxite ore is fused with $ N{{a}_{2}}C{{O}_{3}} $

Answer 1

Answer: (D)

In Halls process, bauxite ore is fused with $ N{{a}_{2}}C{{O}_{3}} $ to form sodium metaaluminate, $ NaAl{{O}_{2}} $ which reacts with water, to precipitate $ Al{{(OH)}_{3}} $ followed by filtration and heating to get pure alumina $ (A{{l}_{2}}{{O}_{3}}) $ $ A{{l}_{2}}{{O}_{3}}\cdot 2{{H}_{2}}O+N{{a}_{2}}C{{O}_{3}}\xrightarrow{{}}2NaAl{{O}_{2}}+C{{O}_{2}}+2{{H}_{2}}O $ $ 2NaAl{{O}_{3}}+3{{H}_{2}}O+C{{O}_{2}}\xrightarrow{333\,K} $ $ 2Al{{(OH)}_{3}}\downarrow N{{a}_{2}}C{{O}_{3}} $ $ 2Al{{(OH)}_{3}}\xrightarrow{1473\,K}A{{l}_{2}}{{O}_{3}}+3{{H}_{2}}O $