A 8.5 $\times$ 10^-³ M solution of a weak acid is 4.6% dissociated at 25°C.In a 8.5 $\times$ 10^-⁴ M solution,the percentage of dissociation would be A)the same B) 4.6% C)

Question

A 8.5 $\times$ 10^-³ M solution of a weak acid is 4.6% dissociated at 25°C.In a 8.5 $\times$ 10^-⁴ M solution,the percentage of dissociation would be A)the same B)> 4.6% C)< 4.6% D)zero E)need to know the K_a of the acid to answer this

Quizplus · Accepted Answer

The percentage of dissociation of a weak acid depends on its concentration and acid dissociation constant (Ka), but not temperature or volume (as given in the question). Therefore, if the concentration of the weak acid is increased while Ka remains the same, the percentage of dissociation will also increase. Since the given solution is more concentrated (8.5 M), the percentage of dissociation will be greater than the 4.6% observed in the previous solution. Therefore, the correct answer is B, greater than 4.6%.

A 85 ×\times× 10-3 M Solution of a Weak Acid Is 4

A 85 $\times$ 10^-³ M Solution of a Weak Acid Is 4