An acid that can provide just one proton is known as a monoprotic or monobasic acid. Polyprotic acids that can provide more than two protons also exist — for example, phosphoric acid H 3 PO 4 , which is triprotic. There is no relationship between the number of hydrogen atoms in the acid molecule and the strength of the acid — this depends on the extent to which the hydrogen in the molecule splits off in solution into hydrogen ions.
An acid with one hydrogen atom that splits off easily will be stronger than one with two hydrogen atoms that do not; for example, hydrochloric acid HCl — a monobasic acid — is a much stronger acid than the dibasic carbonic acid H 2 CO 3. The terms monobasic and dibasic are seldom applied to acids nowadays, but older chemistry textbooks may use them.
Acids are now usually described as monoprotic, diprotic, triprotic and so on. Sulfuric acid , one of the best-known and most widely used acids, is a good example of a dibasic acid. Is hydrochloric acid a monobasic acid? Is formic acid a monobasic acid? Is carbonic acid is a organic acid? Is carbonic acid harmful? What does carbonic acid do to the body? Which one of the acid is dibasic? Which one of the acids is not a dibasic acid? Oxalic acid has two replaceable hydrogen atoms so it is not monobasic acid.
Which one of the acid is tribasic acid? Orthophosphoric acid or phosphoric acid H3PO4 is tribasic acid. Why Sulphuric acid is considered dibasic acid? Why Sulphuric acid is a strong dibasic acid? What is the pH range of acid? What type of acid is H3PO2? Why H3PO3 is a dibasic acid? Is H3PO3 a weak mono basic acid? This website uses cookies to ensure you get the best experience on our website.
Therefore, we can say H 2 CO 3 acts as Bronsted-Lowry acid because of proton donating ability when reacting with a compound such as H 2 O. Note :- Bronsted-Lowry theory is not limited to an aqueous solution, this theory state that a substance is said to be Bronsted-Lowry acid when it donates the proton to other reacting species, the reacting species should be base or very less acidic in nature because according to this theory-.
A substance can function as an Bronsted-Lowry acid only in the presence of a base. The presence of water solution is a must for knowing the acidic nature of substance according to Arrhenius theory.
For knowing whether carbonic acid is strong or weak, look out the basic difference between a strong acid and weak acid-. They have a low pH value and good electrical conductivity properties. They have a high pK a or pH value with moderate electrical conductivity property and weak electrolyte compare to strong acid. Now, Is carbonic acid H 2 CO 3 strong or weak? The strength of an acid depends on its ability to ionize completely or partially in a solution.
So, all molecules of carbonic acid not ionized completely cause fewer hydrogen ions in the aqueous solution and we know the more the hydrogen ion present in the solution, the higher will be the acidic strength of that solution.
The carbonic acid dissociates into two steps, first, it breaks into hydrogen carbonate ion HCO 3 — then again, it HCO 3 — ions dissociate into carbonate ion CO 3 This causes a lower amount of hydrogen ions in the aqueous solution of H 2 CO 3 that ultimately makes it a weak acid in nature.
The acid dissociation constant value K a for H 2 CO 3 is 4. Note :- In weak acid, the backward is more dominating than forwarding reaction, as the splitting ions easily react with each other to reform the acid molecule. A base is a substance that accepts the proton from other compounds or releases OH — ion in an aqueous solution. The strength of basicity in an aqueous solution depends on the number of OH — ions in the solution.
Also, H 2 CO 3 is a proton donor which is also against the property of the base. According to the Arrhenius theory for the base, the substance which produces an OH — ion on dissolving in an aqueous solution is categorized as a base. According to the Bronsted-Lowry theory for the base, the substance which accepts the proton from other compounds and itself makes a conjugate acid categorized as a base.
So, when H 2 CO 3 reacts with the water molecule, it donates the proton to the water molecule and itself makes a conjugate base by release one proton. When one proton loses from acid then a compound is formed which is called the conjugate base of that acid, similarly when one proton is added to the base then a compound is formed which is called conjugate acid of that base.
So, H 2 CO 3 is a weak acid that forms a conjugate base according to the concept of conjugate acid-base pair. Also, check — Conjugate acid-base pairs of HCO 3 —. Enter your email address to subscribe to this blog and receive notifications of new posts by email. Email Address. Notify me of follow-up comments by email.
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