Question

Which of the following sets of solutions of urea
(mol. mass $60 \,g\, mol^{-1}$) and sucrose
(mol. mass $342\, g \,mol^{-1}$) is isotonic?

• A. $ 9.1 \,gL^{-1}$ urea and $6.0 \,gL^{-1}$ sucrose
• B. $ 3.0 \,gL^{-1}$ urea and $3.0 \,gL^{-1}$ sucrose
• C. $ 6.0 \,gL^{-1}$ urea and $9.0 \,gL^{-1}$ sucrose
• D. $ 3.0 \,gL^{-1}$ urea and $17.1 \,gL^{-1}$ sucrose

Answer 1

Answer: (D)

Key Idea Isotonic solutions are those solutions which have same osmotic pressure at a given temperature

Formula for osmotic pressure, $\pi =CRT$