C. A new substance is produced. All others are physical changes.
Answer:
When dissolved in water, acids donate hydrogen ions (H+). Hydrogen ions are hydrogen atoms that have lost an electron and now have just a proton, giving them a positive electrical charge. Bases, on the other hand, mixed with water yield hydroxide ions (OH-).
Answer:
Nitrogen will called as atom or molecule or ion too in the state which it exist means in which form it is present .
