Iron rusts quickly in sea water.
Rain water is slightly acidic, but not enough to cause iron to rust quickly. Distilled water is pure water, and does not contain any minerals that could react with iron to cause rust. River water can contain minerals that can react with iron to cause rust, but it is not as salty as sea water, so it does not cause iron to rust as quickly.
Sea water is a mixture of water and salt. The salt
in sea water can react with iron to form iron oxide, which is rust. The more salt in the water, the faster the iron will rust. This is why iron objects that are exposed to sea water often rust quickly.Iron rust is a red-brown flaky substance that forms on the surface of iron when it is exposed to oxygen and water. Rust is not only unsightly, but it can also weaken iron objects and make them more likely to break. To prevent iron from rusting, it is important to keep it clean and dry. If iron objects are exposed to water, they should be wiped dry as soon as possible.