**Chemical Tests to Show Ionisation Isomerism**

Ionisation isomerism is a type of structural isomerism in which the counter ion of a complex compound is exchanged with a different ion, resulting in the formation of two isomeric compounds. In this case, we need to demonstrate that [Co(NH3)5Cl]SO4 and [Co(NH3)5SO4]Cl are ionisation isomers. To do so, we can perform a few chemical tests that exploit the different properties of these compounds.

**Test 1: Silver Nitrate Test**

- Take a small portion of both compounds separately in two test tubes.
- Add a few drops of silver nitrate (AgNO3) solution to each test tube.
- Observe the color changes.

* [Co(NH3)5Cl]SO4 + AgNO3 → AgCl + [Co(NH3)5SO4]NO3 (White precipitate)
* [Co(NH3)5SO4]Cl + AgNO3 → AgSO4 + [Co(NH3)5Cl]NO3 (White precipitate)

By performing this test, we can see that both compounds form white precipitates, indicating the presence of chloride and sulfate ions. The formation of different precipitates confirms that the counter ions have been exchanged, supporting the concept of ionisation isomerism.

**Test 2: Sodium Hydroxide Test**

- Take a small portion of both compounds separately in two test tubes.
- Add a few drops of sodium hydroxide (NaOH) solution to each test tube.
- Observe the color changes.

* [Co(NH3)5Cl]SO4 + NaOH → [Co(NH3)5OH]SO4 + NaCl (No color change)
* [Co(NH3)5SO4]Cl + NaOH → [Co(NH3)5SO4]OH + NaCl (No color change)

In this test, both compounds do not show any significant color change, indicating that the exchange of counter ions does not affect the overall color of the complex compound.

**Test 3: Barium Chloride Test**

- Take a small portion of both compounds separately in two test tubes.
- Add a few drops of barium chloride (BaCl2) solution to each test tube.
- Observe the color changes.

* [Co(NH3)5Cl]SO4 + BaCl2 → BaSO4 + [Co(NH3)5Cl]Cl2 (No color change)
* [Co(NH3)5SO4]Cl + BaCl2 → BaSO4 + [Co(NH3)5Cl]Cl2 (No color change)

By conducting this test, we can see that both compounds form a white precipitate of barium sulfate (BaSO4), indicating the presence of sulfate ions. The formation of the same precipitate confirms that the exchange of counter ions does not affect the reaction with barium chloride.

**Conclusion**

By performing these chemical tests, we can demonstrate that [Co(NH3)5Cl]SO4 and [Co(NH3)5SO4]Cl are indeed ionisation isomers. The formation of different precipitates with silver nitrate and the lack of significant color changes with sodium hydroxide and barium chloride indicate the exchange of