Passage III

When t-butyl chloride [(CH3)3CCI] is dissolved in an acetone-H2O solution, it reacts with H2O completely to form t-butyl alcohol [(CH3)3COH]:

(CH3)3CCI + H2O (CH3)3COH + H+ + CI-

Acetone is less polar than H2O. Thus, increasing the concentration of acetone in H2O decreases the polarity of the reaction solution.

Figures 1 and 2 show how the electrical conductivity of each of 5 acetone-H2O solutions varied over time after 1 mg of (CH3)3CCI was dissolved in 100 ml of each solution. The conductivity (which increased as the solution's ion concentration increased) stopped increasing when the reaction had run to completion (indicated by the point labeled "RC").

Figures adapted from Peter Keusch, "Kinetics: Hydrolysis of Tertiary Butyl Halides - First Order Reaction." ©2000 by Universitàt Regensburg.

11. The conductivity of the reaction solution at the end of a reaction is . Which of the following graphs best shows how varied with acetone concentration?

Answer and Explanation

Your Answer is

Correct Answer is C

Explanation

According to figure 1 & figure 2, in descending order, it can be seen that:

When the concentration of acetone is 30%, the conductivity will eventually reach about 1.4;

When the concentration is 40%, the conductivity is about 1.35;

When the concentration is 20%, the conductivity is 1.05; when the concentration is 10%, the conductivity is about 0.8;

When the concentration is 50%, Conductivity is the smallest, less than 0.8