What metric measurement is similar to a mile?

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.

Answer explain why it is not possible to deduce a complete order of reactivity.

Which factor is likely to impact the possible number of compounds ?