Question

Why are cis and trans isomers of succinic acid impossible?

Answer 1

Because it is a diacid with no ring function, and no olefinic bond.

Explanation:

Succinic acid, butandioic acid, `HO(O=)C-CH_2CH_2C(=O)OH`, is a linear molecular, which possesses no ring function, and no olefinic bond. Geometric isomerism is not an option for this molecule.