Na --> Na+ + e- E = +2.71
2H2O + 2 e- --> H2 + 2 OH- E = -0.83
Delta E = 2.71 - 0.83 = 1.88 Volts
You know the reaction is spontaneous because Ecell is positive.
Delta Go = - n F Delta E
Delta Go = - 2mol (96485 J/volt mol) (1.88 V)
Delta go = -3.62X10^5 J/mol = -326 kJ/mol
Yes, it is VERY spontaneous.