How many grams of NaNO2 must be added to 1 liter of 1.00 M HNO2 solution in order to prepare a buffer solution with pH = 4.14? pH = 3.14?

Question

My work:

ka = pH(buffer ratio)

4.5 * 10^-4 = 1.000*10^-4.14 (x M of base/1.00 M of acid)

x = 6.21

6.21 M = (6.21 moles/1 L)(1 L) = 6.21 moles

#grams NaNO2 = 6.21 moles (68.9953 g/ 1 mole) = 428 grams??