Introduction to General, Organic and Biochemistry
Introduction to General, Organic and Biochemistry
11th Edition
ISBN: 9781285869759
Author: Frederick A. Bettelheim, William H. Brown, Mary K. Campbell, Shawn O. Farrell, Omar Torres
Publisher: Cengage Learning
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Chapter 16, Problem 16.27P

16-27 Guanidine, p/Ca 13.6, is a very strong base, almost as basic as hydroxide ion.

NH

NH2+

II

II

H2N—C—NH2 + H2O H2N—C—NH2 + OH"

Guanidine

Guanidinium ion

pKb = 13.6

  1. Complete the Lewis structure for guanidine, showing all valence electrons.

  • The remarkable basicity of guanidine is attributed to the fact that the positive charge on the guanidinium ion is delocalized by resonance over the three nitrogen atoms. This delocalization increases the stability of the guanidinium ion relative to the ammonium ion or substituted ammonium ions.
  • Draw three equivalent contributing structures for the guanidinium ion and show by the use of curved arrows how these three contributors are related.

  • Propose an explanation for the fact that protonation occurs on the C=NH nitrogen rather than on one of the —NH., nitrogens. (Hint: Consider the resonance stabilization of the structure formed
  • by protonation on a —NH., nitrogen compared with the resonance stabilization of the structure formed by protonation on the =NH nitrogen.)

  • Predict the N—C—N bond angles in the hybrid.
  • Which is the stronger acid, the ammonium ion or the guanidinium ion?
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    Chapter 16 Solutions

    Introduction to General, Organic and Biochemistry

    Ch. 16 - Prob. 16.11PCh. 16 - Prob. 16.12PCh. 16 - 16-13 Classify each amino group as primary,...Ch. 16 - Prob. 16.14PCh. 16 - 16-15 There are eight primary amines with the...Ch. 16 - Prob. 16.16PCh. 16 - 16-17 Propylamine (bp 48°C), ethylmethylamine (bp...Ch. 16 - 16-18 Account for the fact that 1-butanamine (bp...Ch. 16 - 16-19 2-Me thy 1 propane (bp -12°C), 2-propanol...Ch. 16 - Prob. 16.20PCh. 16 - Prob. 16.21PCh. 16 - Prob. 16.22PCh. 16 - Prob. 16.23PCh. 16 - Prob. 16.24PCh. 16 - Prob. 16.25PCh. 16 - 16-26 The p/fb of amphetamine is approximately 3.2...Ch. 16 - 16-27 Guanidine, p/Ca 13.6, is a very strong base,...Ch. 16 - 16-28 Following is the structural formula of...Ch. 16 - Prob. 16.29PCh. 16 - Prob. 16.30PCh. 16 - Prob. 16.31PCh. 16 - 16*32 Many tumors of the breast are correlated...Ch. 16 - Prob. 16.33PCh. 16 - Prob. 16.34PCh. 16 - 16-35 (Chemical Connections 16B ) What is an...Ch. 16 - Prob. 16.36PCh. 16 - Prob. 16.37PCh. 16 - Prob. 16.38PCh. 16 - Prob. 16.39PCh. 16 - Prob. 16.40PCh. 16 - Prob. 16.41PCh. 16 - Prob. 16.42PCh. 16 - Prob. 16.43PCh. 16 - Prob. 16.44PCh. 16 - Prob. 16.45PCh. 16 - 16-46 Arrange these three compounds in order of...Ch. 16 - Prob. 16.47PCh. 16 - Prob. 16.48PCh. 16 - Prob. 16.49PCh. 16 - Prob. 16.50PCh. 16 - Prob. 16.51PCh. 16 - Prob. 16.52PCh. 16 - Prob. 16.53PCh. 16 - 16-54 Several poisonous plants, including Atropa...Ch. 16 - Prob. 16.55PCh. 16 - Prob. 16.56PCh. 16 - Prob. 16.57PCh. 16 - 16-58 Following is a structural formula of...Ch. 16 - Prob. 16.59P
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