Q6(a). Lead, iron and copper in a rock
A 2.0000 g rock sample contains lead, iron and copper. This sample is dissolved to form a solution containing the three metals. Gravimetric estimation of the metals yielded 0.3188 g of PbSO₄, 0.7282 g of Fe₂O₃ and 0.4787 g of CuCNS. Calculate the percentages of the three metals in the rock sample. (Given atomic weights: Pb = 207.19, S = 32.07, O = 16.01, Fe = 55.85, Cu = 63.54, N = 14.01, C = 12.01)
Model answer
The free solution for 2022 answers questions 1, 2, 4, 7, 8 and 11, the ones picked in its time plan. Question 6 is answered in full in the Geo-Scientist Chemistry Paper I, 2021 to 2025 book, with every part of every paper.
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UPSC Combined Geo-Scientist (Main) Chemistry Paper I: Model Answers 2021 to 2025
- All eleven questions of each paper, with the question printed above its answer
- Titration, gravimetric and nuclear numericals worked with units; structures drawn
- Topic-wise weightage and a topic-wise index
Coversgravimetric factorPbSO4Fe2O3CuCNSpercentage of metal
All parts of Question 6
- 6(a) Lead, iron and copper in a rock10 marks
- 6(b) Nucleation and particle growth10 marks
- 6(c) Volatilisation gravimetry10 marks