Who knows as there are no hydrogen cars in production.
Forever. Hydrogen can be created from water.
Deuterium is a stable isotope of hydrogen and will likely last as long as the rest of the universe.
Honda has hydrogen car. Toyota has hydrogen car. gm is working on hydrogen car.
I believe it was first discovered by Stan Meyers, at least he was the first man to start trying to produce it as a commercial product and take it too the public. This was in the US. The first commercial hydrogen car was not developed that long ago, I am not sure on any specific date though, I would say in the last year or two. You can see example of the <a href="http://www.hydrogencarkit.net/">hydrogen car kit guides</a> here.
hydrogen
As long as the battery is kept charged then it should last 3-5 years.
Any car. As long as you look after it well and do all the maintenance every so often the car will last for a long time.
Depends on the vehicle. As there are no hydrogen cars being sold as of now, it is impossible to list mileage.
If the system does not have any leaks, it will last forever.
About 16 years.
6 years
about 5 years