Reaction of Copper with Fuming Nitric Acid: A Novel Lecture Experiment in Passivation

TCE

The Chemical Educator

ISSN: 1430-4171 (electronic version)

Table of Contents

Abstract Volume 10 Issue 3 (2005) pp 208-210

Reaction of Copper with Fuming Nitric Acid: A Novel Lecture Experiment in Passivation

Vladimir M. Petruševski*, M. Taseska, M. Monković

Institute of Chemistry, Faculty of Natural Sciences and Mathematics, Sts. Cyril & Methodius University, Arhimedova 5, P.O. Box 162, 1001 Skopje, Republic of Macedonia, vladop@iunona.pmf.ukim.edu.mk
Received December 15, 2004. Accepted May 12, 2005.

Published online: 27 May 2005

Abstract. Copper is known to react slowly with diluted nitric acid, giving NO, and very vigorously with concentrated (» 70 %) nitric acid, the product being NO₂. Surprisingly, when copper is brought into contact with pure nitric acid, there is no reaction at all! On dilution of the acid with water, a vigorous reaction occurs producing a great deal of NO₂. We present here a lecture experiment on passivation, which provides an opportunity to discuss the nature of the protective covering that forms and the reasons it is destroyed under dilution.

Key Words: Laboratories and Demonstrations; general chemistry; acid

(*) Corresponding author. (E-mail: vladop@iunona.pmf.ukim.edu.mk)

Article in PDF format (362 KB) HTML format