10-mm. cuvette; heavy curve, with the modified Beckman spectrophotometer, 6- mm. cuvette. the process should be readily adaptable ... 50 ml. H2SO4/1000 ml. soln. All reagents must be made up with extreme care, since contamination in this range of ... be on a plateau for the cerium(lV)- arsenic(III) reaction, since the sensitivity of the catalysis is partially a function of pH (7). ... The potentiometer reading is obtained empirically by employing known colored solutions to get manual visualanbsp;...