Final answer:
The true statements regarding strong bases are that they dissociate almost completely in water, and examples include sodium hydroxide and calcium hydroxide. Statements claiming that strong bases have a higher concentration of hydronium ions than water or a pH below 7 are false.
Step-by-step explanation:
The sentences from the question that are true regarding strong bases are as follows:
- (B) Strong bases dissociate almost completely in water.
- (D) Examples of strong bases include sodium hydroxide and calcium hydroxide.
The incorrect statements are:
- (A) Strong bases actually have a lower concentration of hydronium ions than pure water, not higher.
- (C) Strong bases have a pH above 7, not below 7. A pH below 7 would indicate an acidic solution.
Strong bases, such as NaOH and Ca(OH)2, dissociate nearly completely in water, yielding a high concentration of OH- ions, which is the opposite of hydronium ions. The dissociation makes them strong electrolytes and thus gives them a high pH, typically well above the neutral pH of 7.