Comparative Analysis of the Properties of Acid-Base Indicator of Rose (Rosa setigera), Allamanda (Allamanda cathartica), and Hibiscus (Hibiscus rosa-sinensis) Flowers

Table 8

Acid-base titration with extract as indicator.

Indicator	Strong acid (H2SO4)	Weak acid (CH3COOH)
	Strong base (NaOH)	Strong base (NaOH)
	cm^3	cm^3
Phenolphthalein	12.04 ± 0.15	41.80 ± 0.30
Methyl red	12.04 ± 0.05	44.20 ± 0.15
Bromophenol blue	12.06 ± 0.10	60.50 ± 0.05
Hibiscus (cold extract)	11.70 ± 0.06	25.00 ± 0.15
Hibiscus (methanol extract)	11.50 ± 0.25	25.50 ± 0.60
Allamanda (cold extract)	12.60 ± 0.20	42.60 ± 0.35
Allamanda (methanol extract)	12.00 ± 0.15	36.00 ± 0.50
Rose (cold extract)	13.00 ± 0.60	20.50 ± 0.45
Rose (methanol extract)	13.01 ± 0.40	22.60 ± 0.25

Values are mean ± SD of 3 readings.