when adipic acid is heated,the product is

Adipic acid is the organic compound with the formula (CH₂)₄(COOH)₂. From the industrial perspective, it is the most important dicarboxylic acid. and on heating an organic compound we get carbondioxide and water as products, so also in this case,as it is also an organic compound.

the ans given is ok ,but the given options are succinic anhydride,cyclopentanone,hexane dioic acid,cyclo hexanoate,.so pls give me solution to this.i am lagging behind in my studies  hardly 6months to go.

when both COOH are attached to same carbon atom, CO2 is formed,when COOH are on different carbon atom it gives anhydride.