Formula for Hydrobromic Acid (HBr)

what is an acid? an acid is a substance that increases the hydrogen ion concentration [H+] in a solution. Hydrobromic acid is one of the acid compounds, today we will learn about the formula for hydrobromic acid and its structure.

What is The Formula for Hydrobromic Acid?

The formula for hydrobromic acid is HBr, it is a strong acid formed by the dissolution of hydrogen bromide (HBr) in water. It is therefore a watery solution containing bromide ions and hydronium ions, so it can be used to prepare bromine salts: bromide.

Specification :

  • Molecular Formula : HBr
  • Molecular mass : 80.92 g/mol
  • Melting Point : -88.5 °C
  • Boiling point : -67 °C
  • Density : 1,490 g/cm3 at 25 °C
  • Solubility in water : soluble
  • Appearance : colorless liquid
  • Smell : acrid

Strong, pungent gas forming a heavy cloud in the air, pungent and corrosive, it strongly irritates the skin and mucous membranes. By lowering the temperature, it liquefies into a colorless liquid, then solidifies into white crystals.

A saturated water solution contains 66 percent (by weight) hydrogen bromide at 0 °C, and a solution containing 47.6 percent (by weight) hydrogen bromide boils at 126 °C without composition change (azeotropic mixture). By cooling, it crystallizes with 2 or 4 water molecules.

Lewis Structure of Hydrobromic Acid

The formula for hydrobromic acid can be drawn through Lewis structure. Hydrogen (H) is a non-metal even though it comes from the left side of the periodic table, it’s a non metal.

And so is bromine (Br) comes from the right-hand side of the staircase, so it’s obviously a nonmetal. When two nonmetals get together they form what’s called a covalent bond which is when they share electrons there’s no transfer from one to another.

Let’s draw the Lewis dot diagrams for each atom separately hydrogen is in column 1, so it brings one valence electron with it there’s the one dot. Chlorine is in group 17 all of these atoms bring 7 valence electrons.

Formula for Hydrobromic Acid
Structure of HBr

There we go now hydrogen is happy with two valence electrons that’s something you’re gonna have to memorize it’s called the duplet rule. Chlorine follows the octet rule which means it needs a full eight to be stable, so wouldn’t it be nice if the chlorine could share its electron with hydrogen. That way hydrogen has two and the hydrogen shares its electron with chlorine that way chlorine has eight electrons.

Synthesis of Hydrobromic Acid

Hydrobromic Acid can be prepared in the laboratory with Br2, SO2, and water reaction :

Br2(l) + SO2(g) + 2 H2O(l) → H2SO4(aq) + 2 HBr(aq)

Most typical laboratory preparations are first made by the production of hydrogen bromide (gas) which is then dissolved in water. HBr has been commonly prepared industrially by reacting bromine with either phosphorus or sulfur and water.

Synthesis of Hydrobromic Acid
Synthesis of Hydrobromic Acid

However, it can also be produced electrolytically. Hydrobromic Acid is commercially available in various purities and concentrations.

Acidity of Hydrobromic Acid

Hydrobromic Acid is a strong acid (pKa = 9), stronger than hydrochloric acid but weaker than acidic iodhydric acid. Hydrobromic Acid is one of the strongest known mineral acids. It is totally dissociated from water.

The HBr molecule dissociates (ionizes) to give an H+ ion (a proton). The other ion formed during dissociation is the Br (bromide ion). In a watery solution, the ion H+ ion binds to a water molecule to form an H3O+ hydronium ion.

Uses of Hydrobromic Acid

Hydrobromic Acid is commonly used for the production of inorganic bromide, including zinc bromide, calcium, and sodium. It is a common reagent to create organo-bromic compounds. Some others are separated from HBr. It also catalyzes alkylations and the extraction of certain minerals. The main organic compounds industrially prepared from hydrobromide include allyl bromide, tetrabromo-bis-phenol, and bromoacetic acid.

Hydrobromic Acid Reactions

Some examples of hydrobromic acid reactions can be seen below :

Hydrobromic Acid and Barium Hydroxide

The reaction between hydrobromic acid (HBr) which is a strong acid and barium hydroxide, Ba(OH)2 which is a strong base and so if we start piecing together the molecular equation so we have hydrobromic acid and barium hydroxide both of these in solution.

And it’s up to us now to predict the products and much like the precipitation reactions that we were discussing in the neutralization reactions. This reaction is also double displacement reactions.

And so I would switch the anionic and cationic components of each of these reactants and that should give me the products and so I should get barium bromide (BaBr2) and the other product should be water.

Now again it’s not enough to know the identity of the products we also have to know about their states well water is a liquid if we carry this out at room temperature and we haven’t been old otherwise so.

The equation-balance of the reaction :

2 HBr(aq) + Ba(OH)2(aq) → BaBr2(aq) + 2 H2O(g)

Hydrobromic Acid With Magnesium

When the hydrobromic acid (HBr) reacts to magnesium (Mg) it forms hydrogen gas and a solution of magnesium bromide, MgBr2 (metallic magnesium turns into magnesium ion Mg2+)

The equation-balance of the reaction :

Mg(s) + 2 HBr(aq) → MgBr2(aq) + H2(g)

Hydrobromic Acid Reacts With Potassium Hydroxide

To predict the products of the reaction between hydrobromic acid and potassium hydroxide, we need to first recognize what type of chemical reaction we have in this case. We have an acid and a base mixing together so it’s gonna be a neutralization reaction.

And in neutralization reactions, we end up with salt plus water so that gives us a general idea of what we should end up with we know we’ll have this water this H2O. This is also a double displacement reaction.

The equation-balance of the reaction :

HBr(aq) + KOH(aq) → KBr(aq) + H2O(g)

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