Manipal Medical Manipal Medical Solved Paper-2008

  • question_answer
    Impurities of Cu and Ag from gold are removed by

    A)  boiling impure gold with dil. \[{{H}_{2}}S{{O}_{4}}\]

    B)  boiling impure gold with cone. \[{{H}_{2}}S{{O}_{4}}\]

    C)  electrolytically

    D)  Both [b] and [c]

    Correct Answer: D

    Solution :

     Impurities of Cu and Ag from gold are removed by boiling impure gold with cone.\[{{H}_{2}}S{{O}_{4}}\]and also by electrolytic method. \[Cu+2{{H}_{2}}S{{O}_{4}}\xrightarrow[{}]{heat}CuS{{O}_{4}}+S{{O}_{2}}+2{{H}_{2}}O\] \[2Ag+2{{H}_{2}}S{{O}_{4}}\xrightarrow[{}]{heat}A{{g}_{2}}S{{O}_{4}}+S{{O}_{2}}+2{{H}_{2}}O\] This method is called parting. Cone.\[HN{{O}_{3}}\]can also be used for this purpose.


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