Write the K_b expression for hydrazine and determine the pH of a 0 25 M H_2 NNH_2 (hydrazine) solution (K_b for H_2 NNH_2 is 8.5 times 10^-7). Predict whether aqueous solutions of the following compounds are acidic, basic, or neutral. and explain your choice, by showing the reaction of the acid/base with water, or writing in words what the reaction is: KNO_3 NaCN KCtO Co(NO_3)_2