5 7 6

Fig. I-/(,max as function of activation temperature of ZrO~. mined by titra ting about O. I g of the activated solid suspended in 5mL benzene against 0.1 N solution of n-butyl amine in benzene using the Hammctt indicat-ors'. The basicity was determined by the same.proce-durc by titration against 0.1 N trichloroacetic aeid l 2 • Results and discussion-i-Yuc results on the surface acidity and basicity of the oxides are given in Table I. The Ho.max value of the oxide was determined by plott-ing the acidity and basicity of the Ho of the indicat-or ' 3. llo.max value is the strongest Ho value of the acid sites as well as the equal strongest Ho value of the basic sites. Ho.maxvalue can be regarded as a practical para-meter to represent an acid base property on solids.