富馬酸是一種羧酸。如果存在堿，則羧酸會釋放氫離子。它們以這種方式與所有堿（有機（例如胺）和無機堿）反應。它們與堿的反應，稱為“中和”，伴隨著大量熱量的釋放。酸和堿之間的中和產生水加鹽。具有六個或更少碳原子的羧酸可自由或中度溶于水；碳原子數超過6的化合物微溶于水。水溶性羧酸在水中解離一定程度以產生氫離子。因此，羧酸溶液的pH小于7.0。許多不溶性羧酸與含有化學堿的水溶液迅速反應，并隨著中和生成可溶鹽而溶解。
Fumaric acid is a carboxylic acid. If a base is present, the carboxylic acid releases hydrogen ions. In this way they react with all bases (organic (e.g., amines) and inorganic bases. Their reaction with alkali, called neutralization, is accompanied by the release of a large amount of heat. Neutralization between acid and alkali produces water and salt. Carboxylic acids with six or fewer carbon atoms are free or moderately soluble in water; compounds with more than six carbon atoms are slightly soluble in water. Water soluble carboxylic acids dissociate to a certain extent in water to produce hydrogen ions. Therefore, the pH value of carboxylic acid solution is less than 7.0. Many insoluble carboxylic acids react rapidly with aqueous solutions containing chemical bases, and dissolve with neutralization to form soluble salts.
水溶液中的羧酸和液體或熔融羧酸可與活性金屬反應形成氣態氫和金屬鹽。這樣的反應原則上也對固體羧酸發生，但是如果固體酸保持干燥，則反應會緩慢。甚至“不溶”羧酸也可能從空氣中吸收足夠的水，并在其中充分溶解，從而腐蝕或溶解鐵，鋼和鋁的零件和容器。羧酸與其他酸一樣，與氰化物鹽反應生成氣態氰化氫。對于干燥的固體羧酸，反應較慢。不溶性羧酸與氰化物溶液反應，導致釋放出氣態氰化氫。
Carboxylic acids in aqueous solution and liquid or molten carboxylic acids can react with active metals to form gaseous hydrogen and metal salts. In principle, this reaction also occurs for solid carboxylic acids, but if the solid acids are kept dry, the reaction will be slow. Even "insoluble" carboxylic acids may absorb enough water from the air and dissolve them sufficiently to corrode or dissolve iron, steel and aluminum parts and containers. Carboxylic acid, like other acids, reacts with cyanide salts to form gaseous hydrogen cyanide. For dry solid carboxylic acids, the reaction is slow. The insoluble carboxylic acid reacts with cyanide solution, resulting in the release of gaseous hydrogen cyanide.
羧酸與重氮化合物，二硫代氨基甲酸酯，異氰酸酯，硫醇，氮化物和硫化物的反應會產生易燃或有毒氣體和熱量。羧酸，尤其是水溶液中的羧酸，還會與亞硫酸鹽，亞硝酸鹽，硫代硫酸鹽（生成H2S和SO3），連二亞硫酸鹽（SO2）反應，生成易燃或有毒氣體和熱量。它們與碳酸鹽和碳酸氫鹽的反應生成無害氣體（二氧化碳），但仍會發熱。
The reaction of carboxylic acids with diazo compounds, dithiocarbamates, isocyanates, mercaptans, nitrides and sulfides can produce flammable or toxic gases and heat. Carboxylic acids, especially carboxylic acids in aqueous solutions, react with sulfites, nitrites, thiosulphates (to form H2S and SO3), and dithionite (SO2) to produce flammable or toxic gases and heat. They react with carbonates and bicarbonates to produce a harmless gas (carbon dioxide), but still generate heat.
像其他有機化合物一樣，羧酸可被強氧化劑氧化，并被強還原劑還原。這些反應會產生熱量。各種各樣的產品都是可能的。像其他酸一樣 羧酸可引發聚合反應；像其他酸一樣，它們經常催化（增加反應速率）。在446°（開放容器）下發生部分碳化和馬來酸酐的形成。
Like other organic compounds, carboxylic acids can be oxidized by strong oxidants and reduced by strong reducing agents. These reactions produce heat. All kinds of products are possible. Like other acids, carboxylic acids initiate polymerization; like other acids, they often catalyze. Partial carbonization and maleic anhydride formation occurred at 446 ° in an open container.
