Journal of Chemistry / 2019 / Article / Tab 2 / Research Article
Natural Plant Extracts as Acid-Base Indicator and Determination of Their pKa Value Table 2 Absorption of 10 solutions at pH 7.29, 7.32, 7.36, 7.39, 7.53, 7.59, 7.95, 7.99, 8.14, and 8.52 for all the three follower extracts and methyl red indicator.
Indicator Parameter Absorption of 10 solutions at pH from 7.29 to 8.52 7.29 7.32 7.36 7.39 7.53 7.59 7.95 7.99 8.14 8.52 Impatiens balsamina λ 1 0.028 0.026 0.021 0.020 0.018 0.018 0.017 0.017 0.015 0.015 λ 2 0.361 0.362 0.366 0.370 0.373 0.375 0.376 0.379 0.382 0.416 Acid max 0.325 0.325 0.325 0.325 0.325 0.325 0.325 0.325 0.325 0.325 Base max 0.577 0.577 0.577 0.577 0.577 0.577 0.577 0.577 0.577 0.577 Bauhinia purpurea λ 1 0.069 0.056 0.052 0.044 0.033 0.026 0.020 0.022 0.017 0.013 λ 2 0.581 0.604 0.614 0.646 0.642 0.641 0.659 0.663 0.674 0.712 Acid max 0.132 0.132 0.132 0.132 0.132 0.132 0.132 0.132 0.132 0.132 Base max 0.752 0.752 0.752 0.752 0.752 0.752 0.752 0.752 0.752 0.752 Bougainvillea glabra λ 1 0.07 0.06 0.05 0.05 0.05 0.05 0.04 0.05 0.05 0.04 λ 2 0.04 0.04 0.04 0.04 0.06 0.06 0.07 0.08 0.09 0.13 Acid max 0.11 0.11 0.11 0.11 0.11 0.11 0.11 0.11 0.11 0.11 Base max 0.04 0.04 0.04 0.04 0.04 0.04 0.04 0.04 0.04 0.04 Methyl red λ 1 0.372 0.339 0.286 0.262 0.264 0.261 0.258 0.262 0.258 0.227 λ 2 2.326 2.363 2.392 2.314 2.357 2.368 2.379 2.398 2.452 2.760 Acid max 2.796 2.796 2.796 2.796 2.796 2.796 2.796 2.796 2.796 2.796 Base max 2.42 2.42 2.42 2.42 2.42 2.42 2.42 2.42 2.42 2.42