Inorganic Chemistry> A, B, and C are three complexes of chromi...

A, B, and C are three complexes of chromium (III) with the empirical formula H₁₂O₆CI₃Cr. All the three complexes have water and chloride ion as ligands. Complex A does not react with concentrated H₂SO₄, whereas B and C lose 6.75% and 13.5% of their original mass, respectively, on treatment with concentration H₂SO₄. Identify A, B and C.

Simran Bhatia , 10 Years ago

Grade 11

1 Answers

Aditi Chauhan

Last Activity: 10 Years ago

The complex A does not react with concentrated H₂SO₄ implying that all water molecules are coordinated with Cr³⁺ ion. Hence, its structure would be [Cr(H₂O)₆]CI₃.

The compound B loses 6.75% of its original mass when treated with concentrated H₂SO₄. This loss is due to the removal of water molecules which is/are not directly coordinate to Cr³⁺ ion.

The mass of water molecules removed per mole of the complex

= 6.75/100 * molar mass f the complex = 6.75/100 * 266.5 g = 17.98 g

This corresponds to one mole of water. Hence, the structure of the compound B will be [Cr(H₂O)₅CI](H₂O)CI₂

NOTE : The compound C loses 13.5% of its mass when treated with concentrated H₂SO₄ which is twice fo the mass lost by the compound B. Hence, the structure of the compound C will be [Cr(H₂O)₄ CI₂](H₂O)₂ CI.