KBr is relatively soluble in water, yet its enthalpy of solution is + 19.8 kJ/mol. Which of the following statements provides the best explanation for this behavior? (a) Potassium salts are always soluble in water. (b) The entropy of mixing must be unfavorable. (c) The enthalpy of mixing must be small compared to the enthalpies for breaking up water–water interactions and K–Br ionic interactions. (d) KBr has a high molar mass compared to other salts like NaCl.

Video transcript

Hi everyone for this problem. It reads the entropy of the solution of ammonium iodide is positive 13.7 kg per mole, but it is quite soluble in water. Select the statement that best explains the behavior of ammonium iodide. So we want to select the answer that best explains behavior. Okay, so a ammonium I died is heavier in terms of molar mass compared to other salts. This is true, but it does not explain behavior. So this is not going to be the correct answer. Be ammonium iodide is very soluble in water. This is also true, but it does not explain behavior so that is not correct. See the entropy of mixing for ammonium I died is favorable. So looking at the entropy and it being positive with a positive entropy of solution, entropy of mixing must be favorable. So this is going to be correct. And d the entropy is of breaking up water, water interactions of ammonium bromide ionic interactions are smaller compared to the entropy of mixing. So in terms of behavior for the behavior the water water interactions and the ammonium bro mean ionic interactions is larger than entropy of mixing. So this is going to be false. So this is not the correct answer. So out of all of our options, answer choice C. Is the correct answer. And that's the end of this problem. I hope this was helpful