23. Hydrides

Question 1

What are the types of hydrides based on bonds?

Answer 1

Covalent hydrides (molecular): H₂O, NH₃, HCl

Hydride ions (H^<u>-</u>): NaH, CaH₂

Metallic: CrH

Intermediate: MgH₂

Saline: LiH

Question 2

Hydrolysis of hydrides

Answer 2

_Ionic hydride_s: basic (mechanism - H^-)

_Molecular hydride_s: acidic (H⁺)

Question 3

What is the process of ammonia manufacturing? What are the needed conditions?

Answer 3

NH₂ + 3 H₂ → 2 NH₃ ΔH = -92 kJ/mol

• catalyst (Fe and co-catalysts K₂O, CaO) → to increase reaction rate
• high temperature (400C) → to increase reaction rate
• high pressure (150-250 bar) → to move equilibrium to products