Statement-1: ${\mathrm{Ce}}^{4+}$ can oxidise water. 

Statement-2: ${\mathrm{Ce}}^{4+}$ is a good analytical reagent

${\mathrm{Ce}}^{4+}$ can oxidize water.Because  the "${\mathrm{Ce}}^{4+}$" ion is a potential oxidizing agent. It is due to the fact that the +3 oxidation state is more stable than the +4 oxidation state,

${\mathrm{Ce}}^{4+}$ is a good analytical reagent. 

Because oxidation of water is very slow so ${\mathrm{Ce}}^{4+}$ is a good, analytical reagent.