Question

The normal boiling point of Ethyl acetate is \(77^{\circ}\text{C}\). A solution of non-volatile non-electrolyte solute in ethyl acetate boils at \(78^{\circ}\text{C}\). \(K_b\) for ethyl acetate is \(2.77 ^{\circ}\text{C kg mol}^{-1}\). What is the molality of the solution ?

• A. \(0.361 \text{m}\)
• B. \(0.052 \text{m}\)
• C. \(0.075 \text{m}\)
• D. \(0.25 \text{m}\)

Hint:

Use delta Tb = Kb times m.

Answer 1

The Correct Option is A

Step 1: Quantities
$\Delta T_b = 1$ K and $K_b = 2.77\ \text{K kg mol}^{-1}$.

Step 2: Solve
$m = 1/2.77 = 0.361$ mol per kg of solvent. This is option (A).

Final Answer:
0.361 m. \[ \boxed{\text{(A)}\ 0.361\ \text{m}} \]