Chemistry - Complete d-block Question with Solution | TestHub

A. Na₂Cr₂O₇ is more soluble than K₂Cr₂O₇. This statement is TRUE. Sodium salts are generally more soluble than potassium salts.

B. CrO₄²⁻ is tetrahedral in shape. This statement is TRUE. The central Cr atom has 4 oxygen atoms bonded to it, with no lone pairs, leading to a tetrahedral geometry (sp³ hybridization).

C. Na₂Cr₂O₇ is the primary standard in volumetry. This statement is FALSE. K₂Cr₂O₇ is used as a primary standard because it is not hygroscopic, unlike Na₂Cr₂O₇.

D. Cr₂O₇²⁻ has a Cr-O-Cr bond. This statement is TRUE. The dichromate ion consists of two CrO₄ tetrahedra sharing one oxygen atom, forming a Cr-O-Cr bridge.

Therefore, statement C is false.