Q.7. A 10g sample of only CuS and Cu2S was treated with 100 mL of 1.25 M K2Cr07. The products obtained were Cr^{3+}, Cu^{2+}and SO_2, The exess oxidant was reacted with 50 mL of Fe ^2solution. 25 mlof the same Fe ^{2+}solution required 0 .875M acidic KMnO4, the volume of which used was 20 mL. Find the % of CuS and CuS in the sample.

Q.7. A 10g sample of only CuS and Cu2S was treated with 100 mL of 1.25

1.	Q.7. A 10g sample of only CuS and Cu2S was treated with 100 mL of 1.25 M K2Cr07. The products obtained were Cr^{3+}, Cu^{2+}and SO_2, The exess oxidant was reacted with 50 mL of Fe ^2solution. 25 mlof the same Fe ^{2+}solution required 0 .875M acidic KMnO4, the volume of which used was 20 mL. Find the % of CuS and CuS in the sample.
Answer» Q.7. A 10g sample of only CuS and Cu2S was treated with 100 mL of 1.25 M K2Cr07. The products obtained were Cr^{3+}, Cu^{2+}and SO_2, The exess oxidant was reacted with 50 mL of Fe ^2solution. 25 mlof the same Fe ^{2+}solution required 0 .875M acidic KMnO4, the volume of which used was 20 mL. Find the % of CuS and CuS in the sample.