Попробуйте сменить каталог или выберите один из подходящих результатов поиска ниже: Allow say, the mixture of potassium hexacyanoferrate(III) and phenolphthalein could be the rust indicator. And we use to detect the rusting of the iron nail. And the result is: the tip, head location on the nail seem blue colour; https://ericb269hyk7.blogrelation.com/profile