Which of the two is the stronger base?Give your reason.
hco3- or co3-2
The carbonate ion (CO3^2-) is a stronger base than the bicarbonate ion (HCO3^-).
The reason for this is that the carbonate ion has a higher pH and a greater ability to accept protons (H+ ions) compared to the bicarbonate ion. The carbonate ion has a full negative charge and is able to stabilize the negative charge better than the bicarbonate ion, which only has a partial negative charge. This additional stability allows the carbonate ion to more effectively attract and accept protons, making it a stronger base.
To determine which of the two molecules is the stronger base between HCO3- (bicarbonate ion) and CO3-2 (carbonate ion), we need to consider their relative acid-base dissociation constants (Ka) and their ability to accept protons.
The bicarbonate ion (HCO3-) is a weaker base compared to the carbonate ion (CO3-2). This is because HCO3- can accept a proton (H+) from water to form carbonic acid (H2CO3) by only reacting with one hydrogen ion, while CO3-2 can accept two protons to form carbonic acid.
HCO3- + H2O ⇌ H2CO3 + OH-
CO3-2 + H2O ⇌ HCO3- + OH-
The fact that CO3-2 can accept two protons indicates that it has a greater ability to act as a base compared to HCO3-. Therefore, CO3-2 is the stronger base between the two.
To determine which of the two ions, HCO3- or CO3-2, is the stronger base, we need to consider the basicity of these ions.
One way to evaluate the basicity of a compound or ion is to look at its conjugate acid. The stronger the acid, the weaker its conjugate base, and vice versa. In this case, HCO3- can be considered the conjugate base of H2CO3, while CO3-2 is the conjugate base of HCO3-.
H2CO3 (carbonic acid) is a weak acid that partially ionizes in water to form HCO3- and H+. Since H2CO3 is a weak acid, its conjugate base, HCO3-, would be a weaker base. Therefore, HCO3- is a weaker base compared to CO3-2.
CO3-2 is derived from the strong base OH- by accepting a proton (H+) to form HCO3-, and then accepting another proton (H+) to form CO3-2. Since CO3-2 can accept two protons, it has a greater ability to do so and is therefore a stronger base compared to HCO3-.
To sum up, CO3-2 is the stronger base compared to HCO3- because HCO3- is the conjugate base of a weak acid (H2CO3), while CO3-2 is the conjugate base of a stronger base (OH-).