The aqueous solution is turned bluish black by ferrous sulphate containing a ferric salt.
In aqueous solution it gives a red colour with ferric chloride.
In the ordinary process of soap-making the glycerin remains dissolved in the aqueous liquors from which the soap is separated.
From these results Baeyer concluded that Claus' formula with three para-linkings cannot possibly be correct, for the Q2.5 dihydroterephthalic acid undoubtedly has two ethylene linkages, since it readily takes up two or four atoms of bromine, and is oxidized in warm aqueous solution by alkaline potassium permanganate.
Its aqueous solution has a faint sweet taste, and is dextro-rotatory, the rotation of a fresh solution being about twice that of an old one.