Questions on Kant (Duty Ethics)

1. According to Kant, why should duty rather than personal inclinations or consequences be the basis for morality?
2. How is acting based on a good will an example of deontological ethics?
3. What is the difference between a categorical and a hypothetical imperative?
4. "Act only on that maxim whereby you can at the same time will that it should become a universal law": what does this mean?
5. Why can't lying or selfishness become a universalizable moral maxim (a practical rule of behavior)?