Group VIB

• What group is referred to as the Chromium Group?

  Group VIB
• Name the three elements in the Chromium Group.

  Chromium, Molybdenum, Tungsten
• What are the characteristics of the Chromium Group elements?

  • High melting points
  • Great hardness
  • Excellent resistance to corrosion
• What oxidation states does Chromium form compounds in?

  +2, +3, and +6
• What is the behavior of compounds in the +2 oxidation state of Chromium?

  They are good reducing agents and can be easily oxidized to +3.
• What are the properties of compounds in the +6 oxidation state of Chromium?

  They are strong oxidizing agents and can be reduced to +3.
• What is the most stable oxidation state for Chromium?

  +3
• What oxidation states do Molybdenum and Tungsten exhibit?

  From +2 through +6
• What types of compounds do Chromium, Molybdenum, and Tungsten tend to form?

  They tend to form oxides.
• What are the oxides formed by Chromium, Molybdenum, and Tungsten?

  CrO₂⁺, MoO₂⁺², and UO₂⁺²
• What is the acid-base behavior of Chromium, Molybdenum, and Tungsten?

  • Chromium forms both acidic and basic oxides.
  • Produces hydroxides: Cr(OH)₂ and Cr(OH)₃.
  • Molybdenum and Tungsten are distinctly acidic.
• What precipitate does Cr³⁺ produce when reacted with NaOH?

  A grayish-green precipitate of Cr(OH)₃
• What happens to the grayish-green precipitate of Cr(OH)₃ when excess NaOH is added?

  It dissolves, forming a green solution of NaCrO₂.
• What is the result of reacting Cr³⁺ with Na₂O₂?

  A yellow solution due to Na₂CrO₄ formation.
• What precipitate is formed when CrO₄²⁻ reacts with BaCl₂?

  A yellow precipitate of BaCrO₄.
• Is BaCrO₄ soluble in acetic acid?

  No, it is insoluble in acetic acid.
• What precipitate does AgNO₃ produce when reacted with CrO₄²⁻?

  A brownish-red precipitate of Ag₂CrO₄.
• What is the Perchromic Acid Test (Vanishing Blue Test)?

  • Reacts with H₂O₂ and ether.
  • Forms a blue ethereal layer due to perchromic acid formation.