Initial heating of the phenol and formaldehyde (in the presence of an acid or base to get the reaction going) produced a shellac-like liquid good for coating surfaces like a varnish.

Look at basic acids, bases, and salts. Understand the definition for use in chemistry. Explore the concept of equilibrium and how (when aqueous) basic acids, bases, and salts react.

When you add water to baking powder, the dry acid and base go into solution and start reacting to produce carbon dioxide bubbles.