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

Table 4

Allamanda extracts (cold extract) (initial colour of extract, brown).

Solvent	+	Extract	=	Colour change
ACID
H2SO4	+	Extract	⇒	Brown
CH3COOH	+	Extract	⇒	Brown
BASE
NaOH	+	Extract	⇒	Yellow
KOH	+	Extract	⇒	Yellow

pH = 5.35.