Question

3. Which solution has the highest boiling point?

a) 5.85% solution of NaCl b) 18.0% solution of glucose

c) 6.0% solution of urea d) all have the same boiling point​

Answer 1

Answer:

a:5.85% solution of nacl

Answer 2

The highest boiling point is a) 5.85% solution of NaCl.

• Elevation in boiling point is calculated by the formula = iKbm
• Here, i is Vant's Hoff factor kb is constant and m is molarity.
• Molarity is directly proportional to several moles.
• Number of moles of NaCl=
• $\frac{58.5}{58.5} =0.1$
• Number of moles of urea =
• $\frac{6}{60} =0.1$
• Number of moles of NaCl=
• $\frac{18}{180} =0.1$
• So, all of them have the same number of moles which is 0.1.Now, we will check Vant's Hoff factor i.
• i is a number of ions after dissociation to the number of ions taken initially.
• i is 2 for NaCl and 1 for glucose and urea because NaCl can dissociate to Na+ and Cl- while glucose and urea can't dissociate as they are non-polar.
• So, the boiling point of NaCl is two times of glucose or urea.