Consider the Ka values for the following acids:
Cyanic acid, HOCN, 3.5 ´ 10-4
Formic acid, HCHO2, 1.7 ´ 10-4
Lactic acid, HC3H5O3, 1.3 ´ 10-4
Propionic acid, HC3H5O2, 1.3 ´ 10-5
Benzoic acid, HC7H5O2, 6.3 ´ 10-5
Which of the following is the weakest base?
is it propanionic i am not sure
Cyanic
Cyanic acid
To determine the weakest base, we need to consider the Ka values for the acids provided. The Ka value represents the acid dissociation constant, which indicates the strength of the acid.
The higher the Ka value, the stronger the acid, and the weaker its conjugate base. Therefore, the weakest base is associated with the acid that has the highest Ka value.
Comparing the Ka values given:
Cyanic acid, HOCN: Ka = 3.5 × 10^-4
Formic acid, HCHO2: Ka = 1.7 × 10^-4
Lactic acid, HC3H5O3: Ka = 1.3 × 10^-4
Propionic acid, HC3H5O2: Ka = 1.3 × 10^-5
Benzoic acid, HC7H5O2: Ka = 6.3 × 10^-5
Among these acids, Propionic acid (HC3H5O2) has the lowest Ka value, indicating that it is the weakest acid. Consequently, its conjugate base, C3H5O2-, is the weakest base.
Therefore, the weakest base among the given acids is the conjugate base of Propionic acid (C3H5O2-).
To determine which acid is the weakest base, we need to look at the conjugate bases of these acids. The conjugate base of an acid is formed by removing a proton (H+) from the acid molecule.
The conjugate bases for the given acids are:
1. Cyanic acid: OCN-
2. Formic acid: CHO2-
3. Lactic acid: C3H5O3-
4. Propionic acid: C3H5O2-
5. Benzoic acid: C7H5O2-
When comparing strengths of bases, we look at the stability of the conjugate base. In general, larger, more electronegative atoms are better able to stabilize negative charge than smaller atoms.
Among the conjugate bases, OCN- (from cyanic acid) is the weakest base because it involves a smaller, less electronegative atom (O) compared to the other conjugate bases.
Therefore, the weakest base among the given acids is cyanic acid (HOCN).