An aqueous modified or synthetic acid composition comprising: an acid; a first component comprising: an amine and a carboxylic acid group; a second component comprising: an amine and a sulfonic acid group; wherein said first component and said acid are present in a molar ratio ranging from 1:3 to 1:15, more preferably from 1:3 to 1:12.5. Said acid composition is preferably used in acidizing or stimulating dolomite formations. Disclosed also are methods involving the use of said acid composition.