Hydrogen Bromide and Potassium Chromate are inorganic compounds with chemical formulas, HBr and K2CrO4, respectively. Let us explore more about the reaction between HBr and K2CrO4.
K2CrO4 is a yellow amorphous salt. HBr is a colorless, corrosive oily liquid. K2CrO4 interacts with acids easily due to its basic nature.
In this article, we will learn about a few properties based on the reaction HBr + K2CrO4, like the type of reaction, the product formed, buffer solution, conjugate pairs etc.
What is the product of HBR and K2CrO4?
Chromic Bromide (CrBr3) , Dibromine (Br2), Water (H2O) and Potassium Bromide (KBr) are the products of the reaction between HBr and K2CrO4.
K2CrO4 + HBr → CrBr3 + Br2 + H2O + KBr
What type of reaction is HBr + K2CrO4?
HBr + K2CrO4 is classified as an acid-base reaction, as an acid neutralizes a strong base to produce salt and water.
How to balance HBr + K2CrO4?
The equation for the reaction between HBr + K2CrO4 is balanced using the following steps.
- The general equation is K2CrO4 + HBr → CrBr3 + Br2 + H2O + KBr
- Calculate the number of moles of each element involved in both the reactant and product side of the reaction.
| Elements | Reactant side | Product side |
|---|---|---|
| K | 2 | 1 |
| Cr | 1 | 1 |
| O | 4 | 1 |
| H | 1 | 2 |
| Br | 1 | 6 |
- The number of chromium ions can be balanced by adding 2 to K2CrO4 on the reactant side and CrBr3 on the product side.
- To balance HBr on the reactant side we add 16, whereas we add 3 to Br3, 8 to H2O and 4 to KBr on the product side.
- Thus, the overall balanced reaction is given by –
2K2CrO4 + 16HBr → 2CrBr3 + 3Br2 + 8H2O + 4KBr
HBr + K2CrO4 net ionic equation
The net ionic equation between K2CrO4 + HBr is –
K+ (aq) + Cr6+ (aq) + HBr (aq) = CrBr3 (s) + Br2 (g) + H2O (l) + KBr (s)
The following steps are followed to derive the net ionic equation:
- Write the balanced molecular equation along with the physical state.
- 2K2CrO4 + 16HBr → 2CrBr3 + 3Br2 + 8H2O + 4KBr
- Now, write the ionic form of each of the substances existing in aqueous form and capable of complete dissociation in water. HBr is a weak acid that does not completely dissociate into ions in aqueous form. Hence, the complete ionic equation is –
- K+ (aq) + Cr6+ (aq) + HBr (aq) = CrBr3 (s) + Br2 (g) + H2O (l) + KBr (s)
- We find that the complete ionic equation is identical to the net ionic equation.
- K+ (aq) + Cr6+ (aq) + HBr (aq) = CrBr3 (s) + Br2 (g) + H2O (l) + KBr (s)
HBr + K2CrO4 conjugate pairs
The conjugate pairs of HBr and K2CrO4 are as follows:
- Br– is the conjugate base of HBr.
- Conjugate acid of potassium chromate is chromic acid.
HBr + K2CrO4 intermolecular forces
The intermolecular forces of HBr and K2CrO4 are as follows:
- Dipole-dipole interactions and well as dispersion forces are observed in HBr. This is because HBr is a polar molecule due to the difference in the electronegativity of the H and Br atoms.
- However, for K2CrO4, the major intermolecular force is the ionic bond between the potassium and chromate ions.
HBr + K2CrO4 reaction enthalpy
The enthalpy of the reaction for HBr + K2CrO4 is –393.67 kJ/ mol.
Is HBr + K2CrO4 a buffer solution?
HBr + K2CrO4 is a buffer solution. It is an indirect acidic buffer solution, as the reaction constitutes a weak acid and potassium chromate salt, formed from a weak acid and a strong base.
Is HBr + K2CrO4 a complete reaction?
HBr + K2CrO4 is not a complete reaction, as HBr, a weak halide, remains in the solution due to its poor dissociation.
Is HBR + K2CRO4 an exothermic or endothermic reaction?
HBr + K2CrO4 is an exothermic reaction as the reaction enthalpy is negative.
Is HBr + K2CrO4 a redox reaction?
The reaction between HBr + K2CrO4 is an example of a redox reaction. This is because the the oxidation states of both chromium and potassium are changing on moving from the reactant to product side.
Is HBr + K2CrO4 an irreversible reaction?
HBr + K2CrO4 is an irreversible reaction because of the formation of chromium bromate precipitate, which is insoluble in water.
Is HBr + K2CrO4 a displacement reaction?
The reaction between HBr + K2CrO4 is not a displacement reaction because the number of reactants is not equal to the number of products.
Conclusion
Potassium Chromate and Hydrogen Bromide react to yield Chromium Bromate as a product. This reaction is a very popular displacement reaction. Also, CrBr3 is widely used in organic synthesis as catalyst to polymerize olefins.
Hi, I am Aparajita Bose. I am a Chemistry postgraduate currently working with Micro Labs Advanced Research Centre as a Research Associate. I am passionate about my subject and am excited to educate my readers with precise knowledge. I also want to make the subject fun and easily accessible!
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