Question

The reaction show below has a negative free energy (-∆G) but only occurs over a period of several days. Please classify the cobalt amine complex as

i) inert or labile and ii) stable or unstable

[Co(NH3)6]3+ + 6H3O+ →[Co(H2O)6]3+ + 6 NH4+

Answer 1

i) Lability of a compound is a measure of its Kinetic Stability. Thus, more labile compounds react in a shorter span of time. Here, the reaction proceeds over several days. Hence, the compound is inert.

ii) Stable or unstable complex is a measure of Thermodynamic Stability. Here, the reaction has negative free energy. This means that Cobalt Amine must be unstable because the reaction is spontaneous in the forward direction. Thus, the complex is  unstable.