Calculate the change in Gibbs free energy for each of the following reactions. In each case indicate whether the reaction is spontaneous under standard conditions.
A) H2(g)+Cl2(g)-> 2HCl(g)
B) MgCl2(s)+H2O(l)-> MgO(s)+ 2HCl(g)
C) 2NH3(g) -> N2H4(g)+H2(g)
D) 2NOCl(g)-> NO2(g)+Cl2(g)