Most of the dissolved substance in sea water is:

Question

anonymous · Answer

http://www.britannica.com/EBchecked/topic/531121/seawater/301662/Dissolved-inorganic-substances visit this website..

vincent-lyon.fr · Answer

sodium chloride aka table salt

anonymous · Answer

Yep, @Vincent-Lyon.Fr is correct, NaCl (aq) is the most common (dissociates into ions in the water).

By the way...  The salt in the oceans & seas of the world was in rocks originally but rainwater eroded and dissolved it out slowly, carried down streams and rivers in low concentration, and dumps into streams and lakes.   Some areas have rocks with more soluble salts and if that empties into a a land-locked lake, making it exceedingly salty. Examples include Salt Lake, UT, USA or Dead Sea, Israel-Jordan Border.