The chemistry in Breaking Bad
Hydrofluoric acid to dissolve corpses
Hydrofluoric acid in the show is used to dissolve the corpse of a dead drug dealer. HF acid is a weak acid with a pK a of 3.19. 1 In the series Walter describes hydrofluoric acid as a strong acid, which is incorrect, as a strong acid is defined as an acid with pKa<0. Hydrofluoric acid, however, can cause considerable damage to bones without damage to skin or muscle. The main component of bones (60%) 2 is hydroxyapatite ([Ca ₅ (PO ₄ ) ₃ (OH)]). The fluoride ions can displace the hydroxide and phosphate groups forming calcium fluoride. 𝐶𝑎 2+ +2𝐹 − →𝐶𝑎𝐹 2 The loss of calcium can lead to bone decomposition which at high concentrations can be rapid, with significant decomposition occurring in a few hours. However, it is not strong enough against organic tissue/skin, so it would not be a feasible way to dissolve bodies. Walter details needing a polyethene barrel to dissolve the corpse in as the acid will not be able to corrode through it. Polyethene is made up of non-polar C-C and C-H bonds, which make it very stable and inert and therefore a suitable container for HF. In the show a bathtub is used as a container and the HF is seen to corrode through this. This is accurate as the bathtub seems to be ceramic. Ceramic contains SiO 2 (74%) 3 which can easily react with HF to form SiF 4 as shown.
4𝐻𝐹 + 𝑆𝑖𝑂 2 → 𝑆𝑖𝐹 4 +2𝐻 2 𝑂
Use of fulminated mercury and thermite
Fulminated mercury is used in the show as an explosive which detonates on impact. Fulminated mercury has the molecular structure of Hg(CNO) 2 and it is a greyish small crystal rather than in the form of a large crystal as seen in the show, due to instability. Hg(CNO) 2 is, however, a potent explosive and explodes when exposed to impact or heat as follows.
𝐻𝑔(𝐶𝑁𝑂) 2 →2𝐶𝑂+𝑁 2 +𝐻𝑔
The formation of the N ≡ N(-946kJ/mol) 4 and C ≡ O(- 1075kJ/mol) 4 releases immense energy and the overall enthalpy of the reaction can be calculated in the Hess cycle on the left. This reaction is highly exothermic releasing 488.8 kJ/mol of energy to the surroundings. Comparatively one mole (285g) 5 of Hg(CNO) 2 is equivalent to 116.8 grams of TNT which is approximately 2 Mk 2 grenades. Therefore,
Hess cycle for the detonation of Fulminated mercury
1 ‘Hydrofluoric acid’ PubChem. 2 Feng 2009. 3 Kommanapalli et al. 2018. 4 ‘Properties of atoms, radicals, and bonds.’ 2004. 5 PubChem. 2024. ‘Mercury Fulminate.’
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