Hydrochloric acidHCl

HCl • 36.460 g·mol⁻¹

acidcovalentliquidCAS 7647-01-0PubChem 313 →
HClHCl36.4600 g·mol⁻¹
Molar mass36.460 g·mol⁻¹calc 36.458 • Atomic weights: CIAAW 2021 (conventional atomic weights)
FormulaHClHCl
Classacid • covalentliquid
Composition — HCl
ElementCountMass (g/mol)Mass %
H11.0082.76%
Cl135.45097.24%

Physical properties

State at STP
liquid
Density
1.18 g·cm⁻³ (aq. 37% at 20 °C, 1 atm)
Melting point
247 K (1 atm (conc. aq.))
Boiling point
383 K (1 atm (azeotrope ~20%))

Structure & bonding

Hydrogen chloride gas dissolved in water fully ionizes to H+ and Cl-.

Occurrence & preparation

Stomach acid (dilute). Industrial by reaction of NaCl with H2SO4.

Uses

  • pH adjustment
  • Steel pickling

Safety

Corrosive to skin, eyes, respiratory tract.

Consult current SDS. — consult current SDS before handling.

Constituent elements

Related reactions

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