`A,B` and `C` are three complexes of chromium(III) with the empirical formula `H_(12)O_(6)C_(13)Cr` All the three complexes not react with concentrated `H_(2)SO_(4)` whereas complexes `B` and `C` lose `6.75%` and `13.5%` of their original mass respectively, on treatment on treatment with conectrated `H_(2)SO_(4)` Identify `A,B` and `C` .

Explanation

Complex A does not react with concentrated `H_(2)SO_(4)`
A is `[Cr(H_(2)O)_(6)]CI_(3)`
`[Cr(H_(2)O)_(6)]CI_(3)+H_(2)SO_(4)rarr`Noreaction
Water molecules inside the coordination sphere are not removed by sulphuric acid
Complex `B` loses `6.75%` of its original mass on treatment with concentrated `H_(2)SO_(4)`
`B` is `[Cr(H_(2)O)_(5)CI]CI_(2)H_(2)O`
One mole of `H_(2)O` which is outside the coordination sphere is removed with sulphuric acid
Colecular weight of the complex ` =266.5`
percentage loss m mass `= (18)/(266.5) xx 100 =6.75%`
Complex closes `13.5%` of its original mass on treatment with concentrated `H_(2)SO_(4)`
`C` is `[Cr(H_(2)O)_(4)CI_(2)].CI.2H_(2)O`
Two moles of `H_(2)O` are removed which are outside the coordination sphere
Rercentage loss in mass `=2 xx (18)/(266.5) xx 100 = 13.50%` .