Question

The value of van't hoff factor for na2so4 is 2. What is its degree of dissociation

Answer 1

Answer:

Na2SO4- 2Na+ +SO²-4

Here n= 3

i= 3

Answer 2

Given: the Van't Hoff factor, i  = 2

To Find: degree of dissociation of Na₂SO₄, α.

Solution:

To calculate α, the formula used:

• i = 1 + 2 α
• Na₂SO₄ is a strong electrolyte it will dissociate into 2 sodium ions and 1 sulphate ion.
• The reaction of dissociation is-

                                                   Na₂SO₄       →     2Na⁺  +  SO₄⁻

at time, t=0, concentration ⇒               1                   0           0

at time, t , concentration    ⇒          1 - α                  2α         α

∴   Van't Hoff factor, i  =  (1 - α) + 2α + α / 1

                                 i   =  1 + 2α

Applying the above formula:

i  =  1 + 2α

2 = 1 +  2α

2 - 1  =  2α

2α   =  2 - 1

        =  1

   α   =  1 / 2

  α   = 0.5

Hence, the degree of dissociation is 0.5