Steel results when small carbon atoms occupy interstitial sites in the body-centered…
CHEMISTRY · Single correct · AP · Chemistry · Properties of Substances and Mixtures · Properties of Substances and Mixtures
Problem
Steel results when small carbon atoms occupy interstitial sites in the body-centered cubic lattice of iron. Compared with pure iron, steel is less malleable. Which of the following best accounts for this decrease in malleability?
(a) Carbon donates additional delocalized electrons, weakening metallic bonding and causing brittleness.
(b) Carbon atoms replace some iron atoms, producing lattice strain that prevents layers from sliding.
(c) Interstitial carbon pins dislocations, making it more difficult for planes of iron atoms to slide past one another under stress.
(d) Carbon forms directional covalent bonds with neighboring iron atoms that lock the lattice in place.