HYDROCHLORIC ACID - (7647-01-0)

Introduction

Name: hydrochloric acid; hydrogen chloride
* IUPAC
CAS Number: 7647-01-0
Chemical Formula: HCl
Molar Mass: 36.46094 g
Mass Percent: H 2.7644 %; Cl 97.235 % 

Classification

• inorganic

Uses/Function

• "One of the uses of the muriatic acid sold in hardware stores is to clean mortar from brick. New mortar is calcium hydroxide, which reacts with hydrochloric acid. Mortar sets by reacting with carbon dioxide in the air to produce calcium carbonate, which also reacts with hydrochloric acid. In either case, a solid materials reacts to give a solution." 1

• "The largest single commercial use of hydrochloric acid is in the pickling of steel (iron alloy)." 2

• "The food industry uses hydrochloric acid to make corn syrup from corn startch and to make gelatin from bones." 3

• "Interestingly, hydrochloric acid is present in the gastric juice of the stomach, where it aids in the digestion or breakdown of foods, including the changing of starches into sugars." 4

• "Hydrochloric acid is used in the making of chlorides, in cleaning industrial metals, tile, and brickwork, and in the manufacture of glue, gelatine, and dextrose. The soldering fluid used by plumbers is made by dissolving zinc in an excess of hydrochloric acid. Very small quantities of hydrochloric aci are found in the gastric juice of the stomach and are necessary in gastric digestion. In medicine, very dilute hydrochloric acid is used in certain cases of indigestion." 5

• "is used in the production of metal chlorides, dyes, and many other commercially important products. It is also used on a large scale to dissolve metal oxide coatings from iron and steel prior to galvanizing or enameling." 6

• "28th most produced chemical in the United States in 1995 - 3.0 megatonnes." 7

• "An inorganic acid that is normally present in gastric juice. It destroys fermenting bacteriathat might cause intestinal tract disturbances. Five to 10 mL of a 10% solution of hydrochloric acid in 125 to 250 mL of water is used in treating hypoacidity or achlorhydria." 8

• "Hydrogen chloride and hydrochloric acid have some uses in common, and some that are different from each other. In both dry and liquid form, the largest single use of hydrogen chloride is in the synthesis of organic and inorganic chlorides. A large number of compounds important in commerce and industry contain chlorine, including most pesticides, many pharmaceuticals, and a number of polymeric products.

Hydrochloric acid is also used widely in the processing of metallic ores and the pickling of metals. Pickling is the process by which a metal is cleaned, usually with an acid, to remove rust and other impurities in the metal. Some additional uses of hydrogen chloride and hydrochloric acid include the following:
• In the brining of foods and other materials. Brining is the process by which a material is soaked in a salt solution, usually in order to preserve the material;
• In the treatment of swimming pool water;
• As a catalyst in industrial chemical reactions;
• In the manufacture of semiconductors and other electronic products;
• To maintain the proper acidity in oil wells (to keep oil flowing smoothly);
• For the etching of concrete surfaces;
• In the production of aluminum, titanium, and a number of other important metals.

Both hydrogen chloride and hydrochloric acid pose serious health risks to humans and other animals. The gas is an irritant to the eyes and respiratory system, causing coughing, choking, and tearing, as well as more serious damage to tissues. Hydrochloric acid can burn the skin and mucous membranes. Exposure of only five parts per million of the gas can produce noticeable symptoms of distress, and exposure of more than 2,000 parts per million can be fatal. If hydrochloric acid gets into the eyes, blindness may result. Since hydrochloric acid is present in many household products, users should exercise great care when working with such materials." 9

Physical Properties

Melting Point:*
-114.17°C 10 = 158.98 K = -173.506°F
Boiling Point:*
-85°C 10 = 188.15 K = -121°F

* - 1 atm pressure

Bonding

Bonding: polar covalent
Ionic Character: 29.09 %

Thermochemistry

ΔHf° (g): -22.06 kcal/mol 11 = -92.30 kJ/mol
S° (g): 44.64 cal/(mol•K) 12 = 186.77 J/(mol•K)
ΔGf° (g): -22.78 kcal/mol 13 = -95.31 kJ/mol

Reactions

Ag2S (s alpha orthorhombic) + 2 HCl (aq) → 2 AgCl (s) + H2S (g) 14
2 Al (s) + 6 HCl (aq) → 2 AlCl3 (aq) + 3 H2 (g) 15
BaO2 (s) + 2 HCl (aq) → H2O2 (aq) + BaCl2 (aq) 
BCl3 (g) + 3 H2O (ℓ) → H3BO3 (s) + 3 HCl (g) 16
2 Al (s) + 6 HCl (aq) → 2 AlCl3 (s) + 3 H2 (g) 17
Al(OH)3 (s) + 3 HCl (aq) → AlCl3 (aq) + 3 H2O (ℓ) 18
AlCl3 (s) + 3 H2O (ℓ) → Al(OH)3 (s) + 3 HCl (aq) 19
CaCO3 (s) + 2 HCl (aq) → CaCl2 (aq) + H2O (ℓ) + 1 CO2 (g) 
CH4 (g methane) + 4 Cl2 (g) → CCl4 (ℓ) + 4 HCl (g) 
CH4 (g methane) + 1 Cl2 (g) → CH3Cl (g) + HCl (g) 
2 CHCl3 (aq) + 1 O2 (g) + 2 H2O (ℓ) → 2 CO2 (g) + 6 HCl (aq) 
Cl2 (g) + 1 H2S (aq) → S (s rhombic) + 2 HCl (aq) 20
2 Fe (s alpha) + 6 HCl (aq) → 2 FeCl3 (aq) + 3 H2 (g) 21
Fe (s alpha) + 2 HCl (aq) → FeCl2 (aq) + H2 (g) 22
Fe (s alpha) + 2 HCl (aq) → FeCl2 (aq) + H2 (g) 22
Fe2O3 (s hematite) + 6 HCl (aq) → 2 FeCl3 (aq) + 3 H2O (ℓ) 23
H2 (g) + 1 Cl2 (g) → 2 HCl (g) 24
2 HCl (aq) + 1 MgCO3 (s) → MgCl2 (aq) + H2O (ℓ) + 1 CO2 (g) 25
2 HCl (aq) + 1 K2CO3 (s) → 2 KCl (aq) + H2O (ℓ) + 1 CO2 (g) 26
2 HCl (aq) + 1 Na2CO3 (s) → 2 NaCl (aq) + H2O (ℓ) + 1 CO2 (g) 27
2 HCl (aq) + 1 PbCO3 (s) → PbCl2 (aq) + H2O (ℓ) + 1 CO2 (g) 28
2 HCl (aq) + 1 Na2SO3 (s) → 2 NaCl (aq) + H2O (ℓ) + 1 SO2 (g) 29
2 HCl (aq) + 1 FeCO3 (s) → FeCl2 (aq) + H2O (ℓ) + 1 CO2 (g) 
4 HCl (aq) + 1 MnO2 (s) → 2 H2O (ℓ) + MnCl2 (aq) + 1 Cl2 (g) 30
2 HCl (aq) + 1 Ca(OH)2 (aq) → CaCl2 (aq) + H2O (ℓ) 31
2 HCl (aq) + 1 CaCO3 (s) → CaCl2 (aq) + H2O (ℓ) + 1 CO2 (g) 
5 HClO2 (aq) → 4 ClO2 (g) + HCl (aq) + 2 H2O (ℓ) 32
Mg(OH)2 (s) + 2 HCl (aq) → MgCl2 (aq) + 2 H2O (ℓ) 33
MgCO3 (s) + 2 HCl (aq) → MgCl2 (aq) + H2O (ℓ) + 1 CO2 (g) 34
Na2CO3 (aq) + 2 HCl (aq) → 2 NaCl (aq) + H2O (ℓ) + 1 CO2 (g) 35
Na2S (aq) + 2 HCl (aq) → 2 NaCl (aq) + H2S (g) 36
Na2SO3 (aq) + 2 HCl (aq) → 2 NaCl (aq) + H2O (ℓ) + 1 SO2 (g) 37
NaCl (s) + 1 H2SO4 (aq) → NaHSO4 (s) + HCl (g) 
NaCl (s) + 1 NaHSO4 (s) → Na2SO4 (s) + HCl (g) 
NaHCO3 (s) + 1 HCl (aq) → NaCl (aq) + H2O (ℓ) + 1 CO2 (g) 38
NH4Cl (s) → NH3 (g) + HCl (g) 39
Pb (s) + 2 HCl (aq) → PbCl2 (aq) + H2 (g) 40
PbS (s) + 2 HCl (aq) → PbCl2 (aq) + H2S (g) 41
PCl5 (ℓ) + 4 H2O (ℓ) → H3PO4 (aq) + 5 HCl (g) 
Sb2S3 (s) + 6 HCl (aq) → 2 SbCl3 (aq) + 3 H2S (g) 
Si (s) + 3 HCl (g) → HSiCl3 (g) + H2 (g) 
SiCl4 (g) + 1 O2 (g) + 2 H2 (g) → SiO2 (s quartz) + 4 HCl (g) 42
SiCl4 (ℓ) + 4 C2H5OH (ℓ) → Si(OC2H5)4 (ℓ) + 4 HCl (g) 
Sn (s white) + 2 HCl (aq) → SnCl2 (aq) + H2 (g) 43
Zn (s) + 2 HCl (aq) → H2 (g) + ZnCl2 (aq) 44
ZnS (s sphalerite) + 2 HCl (aq) → ZnCl2 (aq) + H2S (g) 45
2 HCl (aq) + 1 CaCO3 (s) → CaCl2 (aq) + H2O (ℓ) + 1 CO2 (g) 
Mg (s) + 2 HCl (aq) → MgCl2 (aq) + H2 (g) 46
Mn (s alpha) + 2 HCl (aq) → MnCl2 (aq) + H2 (g) 47
K2Cr2O7 (aq) + 6 FeCl2 (aq) + 14 HCl (aq) → 2 CrCl3 (aq) + 2 KCl (aq) + 6 FeCl3 (aq) + 7 H2O (ℓ) 
2 I2 (s) + 5 Cl2 (g) + 6 H2O (ℓ) → 2 HIO3 (aq) + 10 HCl (aq) 48
14 HCl (aq) + 6 FeCl2 (aq) + K2Cr2O7 (aq) → 2 CrCl3 (aq) + 6 FeCl3 (aq) + 2 KCl (aq) + 7 H2O (ℓ) 
6 HCl (aq) + 4 KI (aq) + K2SeO3 (aq) → 2 I2 (s) + 6 KCl (aq) + Se (s hexagonal black) + 3 H2O (ℓ) 49
6 HCl (aq) + 2 KMnO4 (aq) + 5 NaNO2 (aq) → 2 MnCl2 (aq) + 2 KCl (aq) + 5 NaNO3 (aq) + 4 H2O (ℓ) 50

For More Information

Sources

(1) - Ebbing, Darrell D. General Chemistry 3rd ed.; Houghton Mifflin Company: Boston, MA, 1990; pp 93-94.
(2) - Ebbing, Darrell D. General Chemistry 3rd ed.; Houghton Mifflin Company: Boston, MA, 1990; p 94.
(3) - Ebbing, Darrell D. General Chemistry 3rd ed.; Houghton Mifflin Company: Boston, MA, 1990; p 94.
(4) - Ebbing, Darrell D. General Chemistry 3rd ed.; Houghton Mifflin Company: Boston, MA, 1990; p 94.
(5) - Brownlee, Raymond B., Fuller, Robert W., and Whitsit, Jesse E. Elements of Chemistry; Allyn and Bacon: Boston, Massachusetts, 1959; pp 138-139.
(6) - Whitten, Kenneth W., Davis, Raymond E., and Peck, M. Larry. General Chemistry 6th ed.; Saunders College Publishing: Orlando, FL, 2000; p 950.
(7) - Chem. Eng. News, 1995, 73 (26), p 39
(8) - Taber's Cyclopedic Medical Dictionary, 18th ed.; F. A. David Company: Philadelphia, PA, 1997; p 21.
(9) - Schlager, Neil, Weisblatt, Jayne, Newton, David E., and Montney, Charles B. Chemical Compounds Vol. 2; Thomson-Gale: Detroit, MI, 2006; pp 359-61.
(10) - Lide, David R. CRC Handbook of Chemistry and Physics, 84th ed.; CRC Press: Boca Raton, FL, 2003; p 4-60.
(11) - Dean, John A. Lange's Handbook of Chemistry, 12th ed.; McGraw-Hill Book Company: New York, NY, 1979; p 9:4-9:94.
(12) - Dean, John A. Lange's Handbook of Chemistry, 12th ed.; McGraw-Hill Book Company: New York, NY, 1979; p 9:4-9:94.
(13) - Dean, John A. Lange's Handbook of Chemistry, 12th ed.; McGraw-Hill Book Company: New York, NY, 1979; p 9:4-9:94.
(14) - T > 655.728429985855
(15) - T < 3446.09098868316
(16) - T > -736.046044706197
(17) - T > -1901.02881616312
(18) - T < 569.86076986077
(19) - T < 2840.28043339707
(20) - T < 1513.35902795924
(21) - T < 329.497233255253
(22) - T < 2595.22422830518
(23) - T < 255.766022180783
(24) - T > -9239.23923923923
(25) - T > -631.341600901917
(26) - T > -101.960548833579
(27) - T > -107.67666880012
(28) - T > 111.015754306382
(29) - T > 94.7931034482759
(30) - T > 502.192626279033
(31) - T > 1905.15260912373
(32) - T > 5.41045556593644
(33) - T < 1853.32899234901
(34) - T > -631.341600901917
(35) - T > -6.46127639578268
(36) - T < 6690.58295964127
(37) - T > 152.284702427227
(38) - T > 117.422037422037
(39) - T > 618.590757336145
(40) - T > -22.2746331236896
(41) - T > 611.942687905227
(42) - T < 78051.833122631
(43) - T > -141.843971631206
(44) - T < 6650.82108902333
(45) - T > 888.115780684662
(46) - T < 11621.857107294
(47) - T > -8854.45068163593
(48) - T < 413.670891323046
(49) - T > -4769.6335078534
(50) - T < 4646.30019207903