Ca(oh)2 is added to a large beaker of water. how is the solution different from the original water?

solution turns blue litmus to red.

solution turns phenolphthalein pink.

solution has more hydrogen ions.

solution has fewer hydroxide ions.

When Ca(OH)₂ is added to a beaker of water the solution would turn phenolphthalein pink.  Phenolphthalein is a common indicator and is only pink when in basic solutions.  By adding calcium hydroxide, you are turning the solution into a basic solution since the concentration of OH⁻ ions is going up and therefore any phenolphthalein in solution would turn pink.
(answers A,C, and D would happen if you added an acid to the water such as HCl)
I hope this helps.  Let me know if anything is unclear.

Abbreviated as mg-25.