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In acidic medium, K2Cr2O7 shows oxidising action as represented in the half reaction : Cr2O7^2− + XH+ + Ye− → 2A + ZH2O X, Y, Z and A are respectively:

1. 8, 4, 6 and Cr2O3
2. 14, 6, 7 and Cr3+
3. 14, 7, 6 and Cr3+
4. 8, 6, 4 and Cr2O3

Correct answer: 14, 6, 7 and Cr3+

Solution

The correct option is right because in acidic conditions, dichromate ions (Cr2O7^2−) are reduced to chromium ions (Cr3+) while consuming protons (H+) and electrons (e−). The stoichiometry of the reaction indicates that 14 protons and 6 electrons are required to balance the equation, resulting in the formation of 7 water molecules.

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