Chemistry HElp?

Question

Predict whether the dipotassium salt of citric acid (K2HC6H5O7) will form an acidic or basic soluDon in water.

(Ka1 =7.4x10-4;Ka2 =1.7x10-5;Ka3 =4.0x10-7) 

 

Answer 1

Step 1:

The acid dissociation constant for critic acid are and .

The constant for dissociation of the first proton may be denoted as .

The constant for dissociation of the second proton may be denoted as .

The constant for dissociation of the third proton may be denoted as .

Find whether reaction of dipotassium salt of citric acid with water dissociates how many proton.

Chemical equation :

.

Here citric acid dissociates a first proton.

Hence .

The ratio is constant, hence pH depends on the value of k_a.

The higher value of k_a, the solution will be more acidic.

is the highest value among the three.

Hence the reaction of dipotassium salt of citric acid with water dissociates is acidic in nature.

Solution:

The reaction of dipotassium salt of citric acid with water dissociates is acidic in nature.