Write the reaction rate expressions for the following reactions in terms of the disappearance of the reactants and the appearance of products:
(a) H2(g) + I2(g) 2 HI(g)
b) 4NH3(g) + 5O2(g) 4NO(g) + 6H2O(g))
(c) 5Br2 (aq) + BrO3-(aq)+ 6H+ (aq) 3Br2(aq) + 3H2O(l)