Chemical Reaction: Chemical Change Practice Problems

The reaction of A (red) and B (purple) is shown below. Provide the balanced equation.

In an experiment involving the study of the reactivities of Group 1A elements with water, a small piece of potassium metal is added to water. Identify the reactants and products along with their physical states from the following observed chemical reaction. 

2 K, Potassium (s) + 2 H₂O, Water (l) → 2 KOH, Potassium hydroxide (aq) + H₂, Hydrogen (g)