Just as you are reading this, some amount of hydrochloric acid is probably doing its eternal duty inside your belly! Because this is an acid that has vouched to give the process of digestion inside your stomach a kickstart! So next time when you have your favourite dessert or an extra cheesy pizza, rest assured that your stomach is all set to attack those delicacies with hydrochloric acid, once they reach the venue!
Yes, today we are about to learn the relationship that hydrogen and chlorine share with each other, which finally led to the formation of their combination into an independent compound called hydrogen chloride.
Interestingly this compound in its first state of formation is a gas and only when combined with water, this gas convert into an acid– “The Hydrochloric Acid”! Imagine how important this acid is to our lives! In fact, eating food and deriving energy out of it, itself would have been inhibited without the presence of this acid inside our stomach!
All thanks to the Almighty!! Hence it’s imminent that we learn about this particular compound called hydrochloric acid in order to understand its properties and ways of its functioning.
TABLE OF CONTENTS
An aqueous solution of hydrogen chloride is hydrochloric acid, commonly referred to as muriatic acid. It has an unmistakably strong odour and is colourless. It is categorised as a powerful acid. In the digestive tracts of the majority of animal species, including humans, it is a part of the stomach acid. An essential laboratory reagent, concentrated hydrochloric acid is also a highly caustic and combustible industrial chemical.
The name hydrochloric acid is more frequently used by people of English heritage. However, languages like Spanish and German continue to use the phrase "acidum salis," which has historical connotations. The historical name's derivation dates back to the time when rock salt was used to make hydrochloric acid.
Hydrochloric acid is created when the gaseous hydrogen chloride is dissolved in water. It's a straightforward diatomic molecule. One covalent link holds the chlorine atom and hydrogen together. Since the chlorine atom is more electronegative than the hydrogen atom, the bond between hydrogen and chlorine is polar.
It has high acidity. It has no colour and is thick. It smells strongly unpleasant and is corrosive. It is widely utilised in both industries and as a reagent in laboratories. It is employed in the manufacturing of gelatin and the processing of leather. The molarity or concentration of HCl affects physical qualities such as density, melting point, pH, and boiling point.
Hydrogen chloride is a polar compound formed by sharing an electron pair between hydrogen and chlorine. Because chlorine is more electronegative than hydrogen, HCl is a polar covalent molecule.
HCl + H2O → [H3O]+ +Cl-
At the cathode, where water is converted to hydrogen gas as well as hydroxide ions.
2H2O (l)+2e-H2 (g)+2OH-(aq)
Hence in the Chlor-alkali process, during electrolysis:
Hydrogen gas is liberated at the cathode and chlorine gas is liberated at the anode. Sodium ions ,Na+(aq), from the dissolved sodium chloride and hydroxide ions, OH-(aq), from the water stay back and combine to produce sodium hydroxide solution, NaOH (aq). Further hydrogen and chlorine gas reacts to form hydrogen chloride gas, which then when dissolved in water at different concentrations forms the hydrochloric acid.
Cl2 (g) + H2 (g) → 2HCl (g)
Na2O (s)+ 2HCl (aq) 2NaCl (aq) + H2O (l)
K2CO3(aq) + 2HCl (aq) → 2KCl (s)+ H2O (l)+ CO2(g)
Mg (s)+ 2HCl (aq) MgCl2(s) + H2(g)
Fe (s)+ 2HCl (aq) FeCl2(s) + H2(g
2KMnO4 (aq)+ 16HCl (aq) → 2KCl (aq)+ 2MnCl2 (aq)+ 5Cl2(g) + 8H2O(l)
K2Cr2O7 (aq)+ 14HCl (aq) → 2KCl (aq)+ 2CrCl3 (s)+ 3Cl2 (g) + 7H2O(aq)
Na2CO3(s) + 2HCl (aq) → 2NaCl (aq)+ H2O (l)+ CO2(g)
NaHCO3(s) + HCl (aq) → NaCl (aq) + H2O (l)+ CO2(g)
Na2SO3 (s)+ 2HCl (aq) → 2NaCl (aq) + H2O (l)+ SO2 (g)
Hydrochloric acid, a number of enzymes, and a mucus layer that shields your stomach lining make up stomach secretions. The body uses hydrochloric acid to help digest and absorb nutrients like calcium. Additionally, it gets rid of stomach viruses and germs, shielding your body from infection. Hydrochloric acid (HCl), potassium chloride (KCl), and sodium chloride (NaCl) makes up stomach acid. The stomach contain 5,000 parts per million, or about , 0.5 % of hydrochloric acid.
The pH range of a healthy stomach is usually 1.0 to 2.0. Normally, the stomach's low fluid content keeps bacteria out. But at the same time, these pH values almost put battery acid, which can melt steel, in the same class as stomach acid.
Q 1. The molecule of hydrochloric acid is:
HCl consists of two atoms, hydrogen and chlorine. So it is a diatomic molecule. So the correct answer is option C.
Q 2. Hydrochloric acid can be neutralised by:
Hydrochloric acid can be neutralised only by a base. Sodium hydroxide is a base and all others are salt. So option A is the correct answer. Base reacts with the acid to produce salt and water.
HCl (aq)+ NaOH(aq) NaCl (aq)+H2O(aq)
Q 3. HCl dissociates in:
c. Carbon tetrachloride
d. Carbon disulphide
Hydrochloric acid is a polar covalent compound. Hence it dissolves in polar substances like water. There is a dipole-dipole interaction between oppositely charged H+ and Cl- of HCl and H+ and OH- ions of water. All other given options are non-polar in nature. So option B is the correct answer.
Q 4. The smell of hydrochloric acid is:
Hydrochloric acid has a pungent characteristic smell. So option A is the correct answer.
Q.1. How is hydrochloric acid used in the pickling of steel?
Answer: The removal of rust or iron oxide scale from iron or steel before undergoing further processing, such as extrusion, rolling, galvanising, and other procedures, is one of the most significant uses of hydrochloric acid.
Q.2. How is hydrochloric acid produced in the stomach?
Answer: HCl is generated by the abdomen parietal cells. This channel exchanges hydrogen ions from the parietal cell within stomach potassium ions using ATP energy. As a result, the lumen of the stomach contains both hydrogen and chloride ions.
Q.3. Is hydrochloric acid inflammable?
Answer: Hydrochloric acid is not flammable, however, it is very much corrosive and quite poisonous. Chlorine gas, which is very toxic and caustic, and extremely flammable hydrogen gas are formed over the course of a severe fire. Hydrogen gas produced by contact with common metals is particularly flammable.
Q.4. What can be the impacts of HCl on humans?
Answer: The eyes, skin, and mucous membranes are all corrosive to hydrochloric acid. Acute (short-term) inhalation exposure may result in pulmonary edema, ocular irritation, and inflammation of the respiratory tract, nose, and eyes in people.
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