Welcome to PF forums! If you have already looked around, you have seen there are a lot of interesting sections & topics within our forum community. There are also quite a few knowlegable people that are more than willing to help with questions. For homework questions, you will need to show that you've done some thinking about it.
You probably will want to reread this https://www.physicsforums.com/showthread.php?t=94384 which at the top of this topic section.
With regard to your question about mixtures and solutions, chemisttree is actually saying the same thing I am saying to you, but in fewer words.
So tell us what you know about mixtures. What kind of properties have you observed? Do the same for solutions. See if you can make an hypothesis as to how they differ. Once you've shown your thought process, there are many helpful folks here who will guide you in a successful direction towards answering these questions.