2. 

3.

4. Ideally, the answer is (i), that the LED would burn out.  Reality is such that the transistor actually provides enough resistance to keep the LED from frying. 

5. a) Now it should be very close to 10 times longer.
    b) 10 times more capacitance will hold it closed 10 times longer. 

6.  Do it.  The capacitor can't drain through the transistor but does drain through R1.  Now it drains much slower.