NEET AIPMT SOLVED PAPER SCREENING 2005

  • question_answer
                    The mass of carbon anode consumed (giving only carbondioxide) in the production of 270 kg of aluminium metal from bauxite by the Hall process is:                                                             (Atomic mass Al = 27)

    A)                 180 kg       

    B)                 270 kg  

    C)                 540 kg    

    D)                 90 kg

    Correct Answer: D

    Solution :

                    In hall and Heroult process                 \[2A{{l}_{2}}{{O}_{3}}\xrightarrow[{}]{{}}4Al+3{{O}_{2}}\]                 \[4C+3{{O}_{2}}\xrightarrow[{}]{{}}2C{{O}_{2}}+2CO\uparrow \]                 \[2A{{l}_{2}}{{O}_{3}}+4C\xrightarrow[{}]{{}}4aL+2C{{O}_{2}}+2CO\]                 Only for removal of \[C{{O}_{2}},\] following equation is possible                  \[2A{{l}_{2}}{{O}_{3}}+\underset{3\times 12=36}{\mathop{3C}}\,\,\xrightarrow[{}]{{}}\,\underset{4\times 27=108}{\mathop{4Al}}\,\times 3C{{O}_{2}}\]                         \[\because \]              For 108 g of Al, 36 g of C is required in above reaction.                         \[\therefore \]            For 270 g of Al required amount of C                 \[=\frac{36}{108}\times 270=90\,g\]


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