Why Dissolving Salt Is a Chemical Change Therefore, dissolving salt in water is a chemical change. The reactant (sodium chloride, or NaCl) is different from the products (sodium cation and chlorine anion). Thus, any ionic compound that is soluble in water would experience a chemical change.

Dissolving happens when the attractions between the water molecules and the sodium chloride ions overcome the attraction of the ions to each other, causing the ions to separate from each other and mix into the water.

Sodium chloride is readily soluble in water and insoluble or only slightly soluble in most other liquids. It forms small, transparent, colorless to white cubic crystals. Sodium chloride is odorless but has a characteristic taste.

Sodium chloride on heating with sodium vapours acquires yellow colour because sodium chloride crystal suffers metal excess defect with sodium vapours on heated condition. Due to electronic transition at the excited state of sodium atom, it appears yellow.

It is a physical change. When the NaCl dissolves, the Na and Cl ions do break apart. It is not a chemical change because no new chemical bonds are formed. It can also be considered a change of state.

Water reactive chemicals are chemicals that react vigorously with moisture. The most common water sensitive chemicals include sodium, potassium, lithium metals and aluminum alkyls.

The alkali metals (Li, Na, K, Rb, Cs, and Fr) are the most reactive metals in the periodic table – they all react vigorously or even explosively with cold water, resulting in the displacement of hydrogen.

Magnesium, lithium, sodium, potassium, caesium, and rubidium are all metals that will burn and react with water.

Powdered magnesium reacts with water to liberate hydrogen, a flammable gas, though this reaction is not as vigorous as the reaction of sodium or lithium with water.

Other reactions that can be used to start fires include:

• calcium hypochlorite and automotive brake fluid.
• potassium permanganate and glycerin.
• potassium permanganate, acetone, and sulfuric acid.
• sodium chlorate, sugar, and sulfuric acid.
• ammonium nitrate powder, finely ground zinc powder, and hydrochloric acid.

Originally Answered: Can fire occur underwater? Yes. If you supply fuel and oxidizer. There are also flares that burn underwater.

When you pour water onto a fire, the heat of the fire causes the water to heat up and turn into steam. This is a very energy-intensive reaction, and it sucks away the heat (which is a form of energy) of the fire. This leaves the fire without enough energy to keep burning.

If the burning thing is hot enough to vaporise the water, it’s now much less hot, and the water vapour is also blocking oxygen availability. When the water vaporises, it expands a huge amount, so it forms a kind of blanket of steam that smothers the burning thing and stops the air providing oxygen.