What is the importance of activity series?

If a solution is considered basic, then a) the hydroxide ion and hydronium ion concentrations are equal. b) the hydroxide ion concentration is less than the hydronium ion concentration. c) the hydronium ion concentration is greater than the hydroxide ion concentration. d) the hydroxide ion concentration is greater than the hydronium ion concentration.

Achemist has dissolved a certain substance in water. the chemist knows that more of the substance could be dissolved into the water before it stops dissolving. therefore

What type of reaction fuels the processes seen here?