Journal of Chemistry / 2019 / Article / Tab 4

Research Article

Natural Plant Extracts as Acid-Base Indicator and Determination of Their pKa Value

Table 4

Calculated pKa and pH range of indicators.

IndicatorpKapH range

Bougainvillea glabra6.9966 ≈ 7.06.0–8.0
Impatiens balsamina4.3766 ≈ 4.43.4–5.4
Bauhinia purpurea7.0328 ≈ 7.06.0–8.0
Methyl orange3.4003 ≈ 3.42.4–4.4