SRP planning

ok, so i've been thinking about it. I have decided that I might do- instead of just how salt affects water, it will be how different compounds e.g. salt, sugar, baking soda and maybe others- im in the process of working it out. I will do the experiment at home and i've done some research and it shows that generally, they should raise the boiling point of water but for some reason, baking soda seems to decrease the temperature. I am interested in finding out why. I'll do some more research and post the method for my SRP soon.