A somewhat much more general acid-base theory, the Brønsted-Lowry theory, called after Danish chemist john Nicolaus Brønsted and also English chemist cutting board Martin Lowry, specifies an mountain as a proton donor and a base together a proton acceptor. In this theory, the reaction of one acid and base is represented as an equilibrium reaction. Acid (1) + base (2) ⇌ basic (1) + acid (2) (The twin arrows, ⇌, indicate that the assets can re-form the reactants in a dynamic process.)

Acid (1) and base (1) are referred to as a conjugate acid-base pair, as room acid (2) and also base (2). The benefit of this concept is that predictive capacity. Whether the equilibrium lies towards the reactants (reactant-favoured) or the assets (product-favoured) is figured out by the relative strengths the the acids and also bases.

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The Brønsted-Lowry concept is often closely associated with the solvent water. Dissolve an mountain in water to form the hydronium ion and the anion that the mountain is one acid-base reaction. Acids space classified as strong or weak, depending upon whether the equilibrium favours the reactants or products. Hydrochloric acid, a strong acid, ionizes fully in water to type the hydronium and also chlorine (Cl−) ion in a product-favoured reaction. HCl(aq) + H2O (l) → H3O+(aq) +Cl−(aq) utilizing the Brønsted-Lowry theory, the reaction the ammonia and also hydrochloric mountain in water is represented by the following equation: NH3(aq) + HCl(aq) → NH4+(aq) + Cl−(aq) Hydrochloric acid and the chlorine ion room one conjugate acid-base pair, and also the ammonium ion and ammonia are the other. The acid-base reaction is the move of the hydrogen ion native the acid (HCl) to the basic (NH3). The equilibrium favours the weaker acid and also base, in this situation the products. Note that the hydroxide ion go not appear in this equation, a allude differentiating the Arrhenius and Brønsted-Lowry theories.

The Lewis theory

A still more comprehensive acid and also base concept was propose by American physical chemist Gilbert Newton Lewis. In the Lewis theory, bases are identified as electron-pair donors and also acids together electron-pair acceptors. Acid-base reactions involve the mix of the Lewis acid and also base through sharing of the base’s electron pair.

Ammonia is an example of a Lewis base. A pair the electrons situated on the nitrogen atom might be supplied to type a chemistry bond come a Lewis acid such as boron trifluoride (BF3). (In the adhering to equation, the colon represents an electron pair.) H3N: + BF3 → H3N― BF3 Ammonia, water, and many various other Lewis bases reaction with steel ions to form a team of species known as coordination compounds. The reaction to type these varieties is another example the a Lewis acid-base reaction. Because that example, the irradiate blue colour of a equipment of Cu2+ ion in water is because of the 2+ ion. If ammonia is included to this solution, the water molecules attached come copper are replaced by ammonia molecules, and also the beautiful deep blue ion 2+ is formed.

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Substitution reactions space widely supplied in industrial chemistry. Because that example, substituting two of the chlorine atom on chloroform (CHCl3) v fluorine atom produces chlorodifluoromethane (CHClF2). This product experience a more reaction when heated strongly. 2CHClF2(g) → F2C=CF2(g) + 2HCl(g) This latter reaction is an instance of an remove reaction, a hydrogen atom and a chlorine atom being removed from the beginning material as hydrochloric mountain (HCl). The various other product is tetrafluoroethylene, a precursor to the polymer well-known commercially together Teflon.