This demonstration makes a white precipitate by mixing equal amounts of silver nitrate and potassium chloride.
AgNO3 (aq) + KCl (aq) → KNO3 (aq) + AgCl (s)
When sodium hydroxide is dissolved in water it feels warm, which indicates an exothermic reaction.
NaOH (s) → Na+ (aq) + OH- (aq)