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Copper metal can be prepared by roasting copper ore, which contain cuprite `(Cu_(2)S)` and copper sulfide. (CuS) `Cu_(2)S (s) + O_(2) (g) rarr 2Cu (s) + SO_(2) (g)` `CuS (s) + O_(2) (g) rarr Cu (s) + SO_(2) (g)` If ore contains 14.6% impurity in addition to a mixture of CuS and `Cu_(2)S`. Heating 100 gm of mixture produces 70 gm of Cu metal with 90% purity. `[Cu = 63]` Percentage (By mass) of sulphur in the sample is :A. 0.448B. 0.2C. 0.224D. 0.4 |
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Answer» Correct Answer - C `{:(Cu_(2)S,+,O_(2) rarr,2Cu,+,SO_(2),),(a mol,,,2 a mol,,,),(CuS,+,O_(2) rarr,Cu,+,SO_(2),),(b mol,,,(b mol),,,):}` `a xx 158 + b xx 95 = 85.4` …(i) `(2a + b) xx 63 = (70 xx 90)/(100) = 63` `2a + b = 1` …(ii) `a = 0.3, b = 0.4` % by mass of sulphur in sample `= ((0.3 + 0.4) 32 xx 100)/(100)` `= 22.4 %` |
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