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

Table 3

Hibiscus extracts (methanol extract) (initial colour of extract: blood red).

Solvent	+	Extract	=	Colour change
ACID
H2SO4	+	Extract	⇒	Pink
CH3COOH	+	Extract	⇒	Pink
BASE
NaOH	+	Extract	⇒	Pale yellow
KOH	+	Extract	⇒	Pale yellow

pH = 6.52.