| Date | May 2013 | Marks available | 1 | Reference code | 13M.1.hl.TZ2.18 |
| Level | HL | Paper | 1 | Time zone | TZ2 |
| Command term | Determine | Question number | 18 | Adapted from | N/A |
Question
Which compound has the most positive lattice enthalpy of dissociation?
A. NaCl
B. NaBr
C. \({\text{MgC}}{{\text{l}}_{\text{2}}}\)
D. \({\text{MgB}}{{\text{r}}_{\text{2}}}\)
Markscheme
C
Examiners report
Three respondents asked why “most positive” had been used in place of “greatest”. Lattice enthalpy in the IB Data Booklet is given for the endothermic reaction whereas in many data books they are given, with a negative sign, for the reverse reaction. The intention was to prevent misunderstanding.
