What are the dates of the solstices and equinoxes?

In which of these cases are the two wave points considered to be in phase with each other?

Margaret wants to make an orange flavored drink by stirring powdered drink mix into a glass of water. she doesn't like drinks that have small clumps of powdered solid in them, so she wants the drink to be a perfect solution. what factors should margaret not consider when deciding how much powder to add to her glass of water?

The name of the ion, s2-, is: sulfurous ion sulfide ion sulfur ion sulfate ion