Choose the bidentate ligand from the substances below.

A) cyanide ion
B) ammonia
C) EDTA
D) carbon monoxide
E) ethylenediamine

E is the common one.

A bidentate ligand is a ligand that can form two bonds with a central metal ion. Based on that definition, the bidentate ligand from the substances listed would be option E) ethylenediamine. Ethylenediamine is a diamine with two amine groups (NH2) that can form coordination bonds with a metal ion.

To determine the bidentate ligand among the substances provided, we need to understand what a bidentate ligand is.

A bidentate ligand is a molecule or ion that can form two coordinate bonds with a metal ion. This means that it has two atoms or functional groups capable of bonding to the metal center.

Let's look at the substances provided:

A) Cyanide ion (CN-): Cyanide ion is a monodentate ligand since it has only one atom (carbon) capable of bonding to the metal center.

B) Ammonia (NH3): Ammonia is also a monodentate ligand since it has only one nitrogen atom capable of bonding to the metal center.

C) EDTA: Ethylenediaminetetraacetic acid (EDTA) is a polydentate ligand. It has multiple atoms capable of bonding to the metal center, forming multiple coordinate bonds. In the case of EDTA, it can form six coordinate bonds with a metal ion.

D) Carbon monoxide (CO): Carbon monoxide is a monodentate ligand since it has only one carbon atom capable of bonding to the metal center.

E) Ethylenediamine (en): Ethylenediamine is a bidentate ligand. It contains two nitrogen atoms that can form coordinate bonds with a metal ion.

Based on the information above, the bidentate ligand among the substances provided is E) ethylenediamine.