Azo dyes are organic dyes that are used for many applications, such as the coloring of fabrics. Many azo dyes are derivatives of the organic substance azo-benzene, C12H10N2. A closely related substance is hydrazo-benzene, C12H12N2. The Lewis structures of these two substances are

(Recall the shorthand notation used for benzene.)
(a) What is the hybridization at the N atom in each of the substances?
(b) How many unhybridized atomic orbitals are there on the N and the C atoms in each of the substances?
(c) Predict the N-N-C angles in each of the substances.
(d) Azo-benzene is said to have greater delocalization of its π electrons than hydrazo-benzene. Discuss this statement in light of your answers to (a) and (b).
(e) All the atoms of azo-benzene lie in one plane, whereas those of hydrazo-benzene do not. Is this observation consistent with the statement in part (d)?
(f) Azo-benzene is an intense red-orange color, whereas hydrazo-benzene is nearly colorless. Which molecule would be a better one to use in a solar energy conversion device? (See the "Chemistry Put to Work" box for more information about solar cells.)

Transcribed Image Text:

НН Azobenzene Hydrazobenzene 51