Lab # 11

To Observe Color of Red Cabbage Extract at Different pH Assessing Red Cabbage Extract as pH Indicator Anthocynins are responsible of color of many fruits and flowers Some examples are Red Cabbage , Red Roses Cherries etc These are water soluble pigments These are formed by reaction between sugar and protein Bright and dry weather favors its formation The color of Anthocynins is due to conjugated carbon bonds The color of anthocynins is sensitive to pH changes Therefore anthocynins are used as pH indicators Red Cabbage Extract 0 .5M HCl 0

.5M NaOH Twelve Large Test Tubes 250 mL Beaker Pipette Bulb Glass Stirring Rod Serial Box Interface Logger Pro Vernier pH Amplifier IBM Compatible Computer

Lab coat and safety glasses were used Ten test tubes were marked with pH3 , pH4 , pH12 Two test tubes marked and filled with 0 .5M HCl and 0 .5M NaOH Ten test tubes filled up to half mark with Red Cabbage Extract PC was prepared for data collection pH electrode was put into Red Cabbage Extract solution pH and color of the solution was recorded in Power Point Slide pH in the pH3 test tube was adjusted to 3 by adding 0 .5M HCl Color at pH 3 was recorded in Power Point Slide The procedure was repeated for all the pH values up to pH 12 Color of Red Cabbage Extract at Different pH is shown below

pH3 pH8

pH4 pH9

pH5 pH10

pH6 pH11

pH7 pH12 The Red Cabbage Extract changes color with pH The color change was observed in pH range of 3 -12 The extent of color change is significant Therefore , this can be used as pH indicator in this pH range Default Design...