(a) Use data in Appendix 11 to give a quantitative explanation why H 2 can be prepared...

Question:

(a) Use data in Appendix 11 to give a quantitative explanation why H₂ can be prepared from the reaction of Zn with dilute mineral acid, but not from Cu with a dilute acid.

(b) The ion [H₁₃O₆]+ can exist in more than one isomeric form. One that has been structurally characterized is described in terms of [(H₅O₂)(H₂O)₄]⁺, in which an [H₅O₂]⁺ unit containing a strong hydrogen bond is centrally positioned within the [H₁₃O₆]⁺ ion. Draw a schematic representation of this ion and give a description of the bonding within it.

(c) The IR spectrum of gaseous SbH₃ shows absorptions at 1894, 1891, 831 and 782 cm⁻¹. Comment on why this provides evidence that SbH₃ has C_3v rather than D_3h symmetry.

Data from Appendix 11

The concentration of each aqueous solution is 1 mol dm⁻³ and the pressure of a gaseous component is 1 bar (10⁵ Pa). (Changing the standard pressure to 1 atm (101 300 Pa) makes no difference to the values of E^o at this level of accuracy.) Each half-cell listed contains the specified solution species at a concentration of 1 mol dm⁻³; where the half-cell contains [OH]⁻, the value of E^o refers to [OH⁻] = 1 mol dm⁻³, hence the notation E^o_{[OH⁻] = 1}