In the standardization of Na2S2O3 using K2Cr2O7 by iodometry, the equivalent weight of
K2Cr207 is
(1) Molecular weight/2 (2) Molecular weight/6
(3) Molecular weight/3 (4) same as molecular weight

Dear Student,

The iodometry titration of K₂Cr₂O₇, Chromium is being reduced by Na₂S₂O₃ from Cr⁶⁺ in K₂Cr₂O₇, to Cr³⁺, according to the following reaction :

Cr₂O₇^2- + 6 e^- → 2 Cr³⁺

Now, since in this redox titration reduction of Chromium involves a 6 electron change, therefore the equivalent weight of K₂Cr₂O₇ = Molecular weight / 6.

Thus, the correct option is (2).

Hope, this information is helpful.

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