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Melting of water is clearly a physical change, while reaction of $\ce{H2}$ and $\ce{O2}$ is clearly a chemical change. One another fact, putting paint on a canvas is not always a physical change. In fact some paints are manufactured in such a way that during drying, some chemical reactions occur, due to which the paint fixes firmly on the surface.
The dissolution of NaCl in water is a physical change. Because, it's a reversible process. If water evaporates, you get back the salt. The dielectric constant $\epsilon_r$ of water is 80 compared with 1 for air. So, the attractive electrostatic forces between ions are weakened by a factor of 80 when salt is added to water.
This is a chemical change. NaCl is a salt and when immersed in water its crystal structure breaks and gives hydrated ions ($\ce{Na+}$ and $\ce{Cl-}$). This also is a chemical change. The process of dissolution is always a chemical change because there is an interaction between solute and solvent (high or low interaction).
Physical changes change the shape, size or phase of a substance. Crumpling paper, getting a haircut, dissolving salt in water, melting wax, making ice cubes, chopping veggies for tossed salad, growing crystals from a supersaturated solution, grinding metal and slicing bread are all physical changes.
Below undergraduate level, many teachers would maintain that salt dissolution is physical. They are mistaken. Answer link. This question is bound to provoke controversy; it certainly has before. The dissolution of sodium chloride in water is clearly a chemical change. Please, before you say that such dissolution is reversible, read the entirety ...
There is no simple way to extract the gas back out of water. This solubility involved a chemical change. On the other hand, salt NaCl when dissolved in water, it will not chemical react with water per se and you can recover the salt by evaporation. Should I call this a chemical change or a physical change? It does not matter.
Dissolving salt in water does in fact cause a change in chemical structure - the crystalline structure of sodium and chlorine ions in a lattice changes to completely separate sodium ions and chloride ions, each fully solvated by water molecules. This is, of course, a change in physical form, but it is also a change to the chemical formula (NaCl ...
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. NaCl(s) -> NaCl(aq) It is a very common misconception that this process is a chemical change. According to data from AAAS 21% of high school students believe that dissolving is a chemical change ...
The dissolution of ANY IONIC SALT (typically in water) involves the formation of new substances, aquated ions, and the making and breaking of strong chemical bonds. And thus, BY DEFINITION, dissolution of ANY salt in water is A CHEMICAL CHANGE. For the purposes of your question, they are looking for answer #(d)#. Fluoride is the conjugate base ...
And old chesnut, see here. My own opinion is that it is clearly an example of chemical change. Anyway it is discussed in the thread. It is not a question that would be asked at A level, or even at 1st year university.