The addition of sodium acetate to 0.1 M acetic acid will cause
The addition of sodium acetate to 0.1 M acetic acid will cause
The correct option is A increase in its pH value
Common ion effect:
The degree of ionisation of an electrolyte decreases in the presence of a strong electrolyte having a common ion. For example, ionisation of CH3COOH is suppressed in presence of HCl due to common H+ ions.
In this case, adding acetate ion into the solution will drive the reaction backward.
CH3COOH(aq) + H20 (l) ⇋ CH3COO−(aq) + H3O+ (aq)
Adding more sodium acetate will yield more of the common acetate ion, hence suppressing the ionization of the weak acid. Concentration of H3O+decreases and hence pH increases.
A more formal an detailed definition of the common ion effect is :
To the solution of a weak electrolyte, if a solution of strong electrolyte is added which furnishes an ion common to that furnished by the weak electrolyte, the ionization of the weak electrolyte is suppressed.' For example, NH4OH is a weak electrolyte and ionizes to a small extent.
NH4OH ⇋ NH4+ + OH−
When a strong electrolyte furnishing NH4+ or OH−ion is added (e.g., NH4Cl , NaOH, etc.) to NH4OHsolution, the above equilibrium will be shifted to the left because of high concentration of the common ion and thus the ionisation of NH4OHis further suppressed. Similarly, the ionisation of CH3COOH is suppressed by the addition of CH3COONa or HCl. Thus in short; the suppression of ionization of a weak acid or a weak base by adding one of its own ions is known as common ion effect. Since the dissociation constant of an acid (or base) remains constant at a given temperature, the presence of a common ion decreases the degree of dissociation of an acid (or a base).
increase in its pH value
Common ion effect:
The degree of ionisation of an electrolyte decreases in the presence of a strong electrolyte having a common ion. For example, ionisation of CH3COOH is suppressed in presence of HCl due to common H+ ions.
In this case, adding acetate ion into the solution will drive the reaction backward.
CH3COOH(aq) + H20 (l) ⇋ CH3COO−(aq) + H3O+ (aq)
Adding more sodium acetate will yield more of the common acetate ion, hence suppressing the ionization of the weak acid. Concentration of H3O+decreases and hence pH increases.
A more formal an detailed definition of the common ion effect is :
To the solution of a weak electrolyte, if a solution of strong electrolyte is added which furnishes an ion common to that furnished by the weak electrolyte, the ionization of the weak electrolyte is suppressed.' For example, NH4OH is a weak electrolyte and ionizes to a small extent.
NH4OH ⇋ NH4+ + OH−
When a strong electrolyte furnishing NH4+ or OH−ion is added (e.g., NH4Cl , NaOH, etc.) to NH4OHsolution, the above equilibrium will be shifted to the left because of high concentration of the common ion and thus the ionisation of NH4OHis further suppressed. Similarly, the ionisation of CH3COOH is suppressed by the addition of CH3COONa or HCl. Thus in short; the suppression of ionization of a weak acid or a weak base by adding one of its own ions is known as common ion effect. Since the dissociation constant of an acid (or base) remains constant at a given temperature, the presence of a common ion decreases the degree of dissociation of an acid (or a base).
