Give one chemical test as an evidence to show that [Co(NH3)5Cl]SO4 and [Co(NH3)5(SO4)]Cl are ionization isomers.

When ionization isomers are dissolved in water, they ionize to give different ions. These ions then react differently with different reagents to give different products.
[Co(NH3)5Cl]SO4 + Ba+2 → BaSO4↓ (White ppt.)
[Co(NH3)5SO4]Cl + Ba+2 → No reaction
[Co(NH3)5Cl]SO4 + Ag+ → No reaction
[Co(NH3)5SO4]Cl + Ag+ → AgCl↓ (White ppt.)