Acidity/basicity of binary compounds of hydrogen

 

  • The hydogen-containing compounds in blue above are ionic.
    These are basic because hydride ion (H–) is a strong base.

    H– + H2O → H2(g) + OH–
    NaH(s) + H2O → H2(g) + NaOH(aq)
     
  • The hydrogen-containing compounds at the right above are molecular.
    Even though hydrogen is the more positive atom in these compounds, they are not all acids (proton donors).
    Acidity increases across a row and down a group as shown above.

    HCl + H2O → H3O+ + Cl–  strong acid
    HF + H2O H3O+ + F–      weak acid
Dr Sheila Woodgate
© The University of Auckland 2002