00:00Hi friends, a never-ending adventure is a learning adventure because every day there will be something new to learn.
00:09Given several solutions now, we are asked to determine the solution mixture that is closest to the ideal solution.
00:20Before answering this question, consider the gas particles in this tube.
00:26Each gas particle moves freely anywhere independently.
00:30The movement of one particle is not affected by the other particles, because there is no force acting on each
00:38particle.
00:41This is the definition of an ideal gas.
00:46Physically, every ideal gas will satisfy the equation PV equals nRT.
00:54So, what about an ideal solution?
00:58What is an ideal solution?
01:03If viewed on a molecular scale, the distance between each molecule is close to each other.
01:09The movement of molecules is certainly more limited than the movement of gas particles.
01:16However, the particle distance has a certain average value.
01:22Suppose we have two different solutions.
01:28The two solutions are mixed in the same container.
01:33This mixture will be an ideal solution when the distance between the molecules remains the same.
01:39This means there are no interaction forces between the molecules.
01:45Because the distance between the molecules does not change, the volume of the mixture is the usual sum of the
01:52volumes of each solution.
01:55This is an ideal solution.
02:00When this mixture forms a non-ideal solution, there may be interaction forces.
02:08It's possible for a molecule to attract another molecule.
02:12This causes the distance between molecules to become shorter.
02:17This causes the volume of the mixture to decrease.
02:23Or, some molecules repel other molecules.
02:28This causes the distance between molecules to become wider.
02:32This causes the volume of the mixture to increase.
02:39Physically, we can see the ideality of a solution from its total pressure.
02:45When the vapor pressure of the mixture is linear, or obeys Raoult's law, it is an ideal solution.
02:53It's possible for fewer molecules to evaporate, meaning each molecule is attracted to each other.
03:00The curve is concave downward.
03:04This is not an ideal solution.
03:10It is possible that the molecules are more volatile, meaning that each molecule repels each other.
03:17The curve is convex upwards.
03:20This is also not an ideal solution.
03:25In general, the attractive forces between molecules and different polarities make the solution even more non-ideal.
03:33So, we will determine the polarity of each solution.
03:40Now let's look at some solutions to be mixed.
03:46In water, acetic acid, methane, and phenol, there are hydrogen bonds.
03:54In ammonia and methylamine, there are polar bonds.
04:00In benzene and toluene, there are nonpolar bonds.
04:07Molecules in a mixture of nonpolar and nonpolar solutions will not interact with each other.
04:13The resulting solution mixture will approach an ideal solution.
04:20I think the correct answer is D.
04:27Happy learning, everyone!
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