JEE Advanced levelSingle correct optionDifficulty 3 of 3cc069
Compound [Co(NHX3)X5Br]SOX4 gives a white precipitate with BaClX2 and none with AgNOX3. Its ionisation isomer Y gives no precipitate with BaClX2 but a pale yellow precipitate with AgNOX3. Y is named
Apentaamminebromidocobalt(III) sulfate
Bpentaamminebromidosulfatocobalt(III)
Cpentaamminesulfatocobalt(III) bromide
Dpentaamminesulfatocobalt(II) bromide
Answer: C
Y must release free bromide (pale yellow AgBr) and keep sulfate inside the sphere: [Co(NHX3)X5(SOX4)]Br. Sulfate is a 2− ligand, so the cation is x−2=+1 and Co is +3. The name is pentaamminesulfatocobalt(III) bromide.