Question

Distinguish between the terms spontaneous and instantaneous. Give an example of a process that is spontaneous but very slow, and one that is very fast but not spontaneous.

Short answer

Spontaneous happens naturally within some conditions. Instantaneous is an event occurring right away. An example of a process that is spontaneous but very slow is decay of Uranium$-238$, and one that is very fast but not spontaneous is an exploding dynamite.

Step-by-step solution

Concept Introduction.

A spontaneous reaction is one in which the energy is released suddenly and the reaction occurs quickly. Instant reaction releases free energy and transitions to a more stable state.

Difference between Spontaneous and Instantaneous.

A spontaneous process is one that occurs naturally under certain conditions. This means that reactants produced products on its own. All the decay processes occur spontaneously, Uranium$-238$ decay is an example of a spontaneous process that is very slow, exhibiting a half-life of more than four billion years.

An instantaneous process is obviously a process which occurs right away, virtually instantly. Something like this could be exploding dynamite. Time consumed for this reaction type less than time consumed of spontaneous reaction.

Therefore, spontaneous means naturally occurring and instantaneous means occurring right away.