Login

For [CrCl3•xNH3], elevation in boiling point of one molal solution is triple of one molal aqueous solution of urea. Assuming 100% ionisation of the complex molecule, calculate the value of 'x'.

6 days n no answer. ..experts plz answer it..plz plzz plzzzzzz_/_
  • 8
View Full Answer
ans is 5. 
  • -2
  See solvent in both the cases is same that is water. So Kf (cryoscopic constant) is same for both the cases. We can say that delta T is directly proportional to molality. Now the molality of urea is one and since it does not dissociates it is one mole of urea per  kilogram of solvent. But for the complex let it dissociate to n ions so if there is one molal solution of complex it will dissociate to n ions which means n moles of sparingly soluble solute causing n times more elevation in boiling point. Since it causes 3 times elevation (given) it means n=3. This means the complex dissociated to 3 ions which is like [CrCl.xNH3]Cl2 --->[CrCl.xNH3]+2 + 2Cl-  now as coordination number of Cr+3 is 6 so x=5 (since there is one Cl inside the complex) Hope u got it 😊😊😊
  • 7
molality and Ke Of both solutions are equal. So ∆Tb should be equal if vantHoff coeff. same. i =1 for urea it means for co-ordination comp. it should be i=3. Means numbers of ions should be 3 because i=n. Cr+3 co-ordination number is 6. So in bracket total no of Cl+NH3 should be=6 so with one Cl only 5NH3 present in bracket and two Cl out from bracket.So x=5
  • 2
What are you looking for?