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.

IndicatorParameterAbsorption of 10 solutions at pH from 7.29 to 8.52
7.297.327.367.397.537.597.957.998.148.52

Impatiens balsaminaλ 10.0280.0260.0210.0200.0180.0180.0170.0170.0150.015
λ 20.3610.3620.3660.3700.3730.3750.3760.3790.3820.416
Acid max0.3250.3250.3250.3250.3250.3250.3250.3250.3250.325
Base max0.5770.5770.5770.5770.5770.5770.5770.5770.5770.577

Bauhinia purpureaλ 10.0690.0560.0520.0440.0330.0260.0200.0220.0170.013
λ 20.5810.6040.6140.6460.6420.6410.6590.6630.6740.712
Acid max0.1320.1320.1320.1320.1320.1320.1320.1320.1320.132
Base max0.7520.7520.7520.7520.7520.7520.7520.7520.7520.752

Bougainvillea glabraλ 10.070.060.050.050.050.050.040.050.050.04
λ 20.040.040.040.040.060.060.070.080.090.13
Acid max0.110.110.110.110.110.110.110.110.110.11
Base max0.040.040.040.040.040.040.040.040.040.04

Methyl redλ 10.3720.3390.2860.2620.2640.2610.2580.2620.2580.227
λ 22.3262.3632.3922.3142.3572.3682.3792.3982.4522.760
Acid max2.7962.7962.7962.7962.7962.7962.7962.7962.7962.796
Base max2.422.422.422.422.422.422.422.422.422.42