Give evidence that [Co(NH3)5Cl]SO4 and [Co(NH3)5(SO4)]Cl are ionisation isomers.

These compounds give different ions in aqueous solution. This can be tested by using AgNO3 solution and BaCl2 

[Co(NH3)5Cl]SO4(aq)+ BaCl2(aq)→BaSO4(ppt)

[Co(NH3)5Cl]SO4(aq)+ AgNO3(aq)→ no reaction

[Co(NH3)5(SO4)]Cl(aq)+ BaCl2(aq) → no reaction

[Co(NH3)5(SO4)]Cl(aq)+ AgNO3(aq)→AgCl(ppt)

Hence they give different precipitates with different solutions. Thus they are ionisation isomers.