Q. Sea water is saltier than rain water because:
Answer: Rivers wash away salts from earth and pour them into the sea
Notes: Sea water is salty or saline because rainwater dissolves the salt minerals found in soil and rocks as it travels through rivers and streams en route to the sea The rain that falls on the land contains some dissolved carbon dioxide from the surrounding air. This causes the rainwater to be slightly acidic due to carbonic acid. The rain physically erodes the rock and the acids chemically break down the rocks and carries salts and minerals along in a dissolved state as ions. The ions in the runoff are carried to the streams and rivers and then to the ocean which makes them salty.