how would i create a 100mL solution of 0.1N nitric acid using 6.25N nitric acid?

Answer 1

N*mL = N*mL
0.1 N*100 mL = 6.25N * mL.
Solve for mL. That will be # mL needed of the 6.25 N solution. Make the final volume to 100 mL.