Can a hypothesis be disproved by a single experiment.?

Yes. A hypothesis describes what we expect to happen in an experiment. If we do the experiment and something different happens, then our hypothesis is "falsified", or demonstrated to be false.

In that case, we'll need to reconsider our hypothesis to determine how it was wrong. We can revise our hypothesis and then conduct a different experiment to test it.

It's easy to demonstrate that a hypothesis is incorrect, but it is impossible to prove that it is true.