Passage III
The chemical equations in Figure 1 show what occurs when 1 formula unit of each of 3 salts dissolves in H2O.
The conductivity of a solution is a measure of its ability to conduct electricity. Figure 2 shows how the conductivity (in millisiemens per centimeter, mS/cm) of an 18°C aqueous solution of each of the 3 salts varies with concentration. Concentration is measured as millimoles of salt per liter of solution (mmol/L). A millimole is 6 x 1020 formula units of any salt.
Figure 3 shows how the conductivity of an aqueous NaCl solution at 4 temperatures with concentration (measured as % NaCl by mass).
12. At aqueous Na2SO4 solution at 18°C has a conductivity of 12 mS/cm. According to Figure 2, the Na2SO4 concentration of this solution is closest to which of the following?
Your Answer is
Correct Answer is H
Explanation
See figure 2, when the ordinate conductivity of Na2SO4 solution is 12, the abscissa concentration is about 75 mmol/L