What would happen to the ecosystem if there were no nitrogen-fixing bacteria

Essentially all the available nitrogen for life in the form of nitrates and ammonia would eventually disappear. Nitrogen is needed to make proteins and other chemicals so it is required for all life to exist. It gets recycled so it would take many decades in most places before the available nitrogen ran out. Many crops like beans depend on it. Humans can manufacture it but it would be hard on the ecosystems of the world and eventually probably lead to the extinction of all the ecosystems of the world.

Hope this helps!

Hno3(aq) → h+(aq) + no3−(aq). picture ii best represents the strong acid hno3. strong acids are strong electrolytes

It shows that the experiment is designed properly.