Equivalent Weight of Nitric Acid
| Value | 0.063012 kg/mol |
| Status | Measured: ± 0.000004 kg/mol (0.000063 relative) |
| Source | IUPAC |
| Categories | Chemistryequivalent-weightwater-treatment |
| gram per mole | 63.012 g/mol |
| kilogram per kilomole | 63.012 kg/kmol |
| milligram per millimole | 63.012 mg/mmol |
| pound per pound-mole | 63.012 lb/lb-mol |
| dalton (as molar mass) | 63.012 Da |
| kilogram per mole | 0.063012 kg/mol |
| kilodalton (as molar mass) | 0.063012 kDa |
Learning zone
Nitric acid is monoprotic, so its equivalent weight is its molar mass: 1.008 + 14.007 + 3 × 15.999 = 63.012 g/eq. Per equivalent it is the heaviest of the three mineral acids — you feed 63 g where sulfuric needs 49 and hydrochloric 36.5 — which usually rules it out on cost alone for routine alkalinity reduction. It gets specified anyway where its anion is the least-bad option: nitrate neither scales like sulfate nor pits like chloride, and on stainless steel nitric acid actually builds the passive film rather than attacking it, which is why it is the standard passivation acid.
The caveat is biological rather than chemical. Nitrate is a nutrient, and dosing nitric acid into an open cooling tower amounts to fertilising it — algae and biofilm respond enthusiastically, and the biocide budget pays for what the acid budget saved. The same 63.012 also converts nitrate analyses: 62.00 g/mol of NO₃⁻ carries 14.007 g of nitrogen, the arithmetic behind the "as N" versus "as NO₃⁻" reporting split that catches out every new operator.