The equivalent conductivity of monobasic acid at infinite dilution is  348 ohm^{-1}cm^2eq^{-1} . If the resitivity of the solution containing 15 g acid in 1 litre is 18.5 ohm cm , what is the degree of dissociation of acid ?

  • Option 1)

    45.9 %

  • Option 2)

    40.2 %

  • Option 3)

    60.4 %

  • Option 4)

    150.7 %

 

Answers (1)
V Vakul

As we learnt in 

Application of Kohlrausch's law -

Determination of Degree of dissociation of weak electrolytes.

- wherein

Degree of dissociation

\alpha = \frac{\Lambda m}{\Lambda_{m}^{0} }

 

Conductivity= \frac{1}{resistivity}= \frac{1}{18.5}\, \, ohm^{-1}cm^{-1}

Degree of dissociation,\alpha =\frac{\Lambda ^{c}m}{\Lambda ^{\infty }m}

 

\Lambda ^{c}m=\frac{k \times 1000}{C_{m}}  k=conductivity ,  C_{m}=Molar concentration

C_{m}=\frac{15}{49\times 1}= 0.306m

\therefore \Lambda _{m}^{c}=\frac{1000}{18.5\times 0.306} =176.65\ ohm^{-1}cm^{2}mol^{-1}

\therefore degree of dissociation,\therefore \alpha =\frac{176.65}{348}=0.507

\therefore Solution is 4

 


Option 1)

45.9 %

Incorrect

Option 2)

40.2 %

Incorrect

Option 3)

60.4 %

Incorrect

Option 4)

150.7 %

Correct

Preparation Products

Knockout BITSAT 2021

It is an exhaustive preparation module made exclusively for cracking BITSAT..

₹ 4999/- ₹ 2999/-
Buy Now
Knockout BITSAT-JEE Main 2021

An exhaustive E-learning program for the complete preparation of JEE Main and Bitsat.

₹ 27999/- ₹ 16999/-
Buy Now
Exams
Articles
Questions