aqueous cations

• what do you add to positive ions to test?

  add dilute sodium hydroxide
• what is formed when you add dilute sodium hydroxide to calcium 2+?

  • a white precipitate forms
  • doesnt dissolve in excess NaOH
• what is formed when you add dilute sodium hydroxide to copper 2+?

  • a light blue precipitate forms
  • the precipitate does not dissolve in excess NaOH
• what is formed when you add dilute sodium hydroxide to iron 2+?

  • a green precipitate forms
  • the precipitate does not dissolve in excess NaOH
• what is formed when you add dilute sodium hydroxide to iron 3+?

  • a red-brown precipitate forms
  • the precipitate does not dissolve in excess NaOH
• what is formed when you add dilute sodium hydroxide to zinc 2+?

  • a white precipitate forms
  • the precipitate dissolves in excess NaOH
• what is the difference between calcium 2+ and zinc 2+?

  even though they both create a white precipitate, Ca2+ does not dissolve in excess NaOH whereas Zn2+ does.
• what is formed when you add dilute sodium hydroxide to magnesium 2+?

  • white precipitate forms
  • does not dissolve in excess NaOH