Bread and Bleach
To find out what chlorine smells like, just go to the swimming pool. The funny smell of swimming pools is the smell of chlorine. Depending on where you live, you might also smell this in your drinking water when it comes out of the tap, or in your shower. The chlorine in the water kills bacteria so they won't make you sick.
You can also see for yourself that chlorine kills bacteria. Leave a slice of bread out until it gets moldy. Then cut it in half, making sure to get some moldy spots in each half. Pour a little bleach on one half, and leave the other half alone. Then come back and check on them every day for a while. What differences do you see?