1) Personally, I like soup. A lot. It tastes good and let's just say it serves my lazy needs of not wanting to chew on anything. So soup sounds like a great idea huh? But.. in Chemistry....
H2O + NaCl -> HCl + NaOH
Water + Common Salt -> Hydrochloric Acid + Sodium Hydroxide
Let's just say it seems pretty harmless. Hydrochloric acid and sodium hydroxide IF you have no idea what they are. But now, let's just say HCl has a pH value of around 1. And that is a very potent and highly acidic acid. Ok, now Sodium Hydroxide, pH value of 13. And that is a very very corrosive and a highly alkaline alkali. So if those two react, we will be ingesting highly acidic acids and highly alkaline alkali which doesn't sound too good, even if they neutralises each other (for your information, they do)
However, don't worry. Usually it happens in a reverse way, which means
HCl + NaOH -> H2O + NaCl
So, don't worry.. This probably doesn't happen. That's my assumption. You never know ;)
2) This is a video that is kind of viral on Facebook so I thought I will share this here before I explain anything. The adding of mercury (II) thiocyanate can be quite tedious so you can skip that if you want. But the reaction is really cool.
http://chemistry.about.com/od/fireworksprojects/a/pharaohs-snakes.htm
Chemistry don't seem that bad after all, huh? Hope this helps! Have fun :)