(b) phenol red (phenol sulphonephthalein) Of the two colour changes undergone by this
indicator only the one at pH 6.8–8.4 is commonly employed.
(c) methyl orange
(b) phenol red (phenol sulphonephthalein) Of the two colour changes undergone by this
indicator only the one at pH 6.8–8.4 is commonly employed.
(c) methyl orange