Answer:
C. a positive calcium ion and a negative oxygen ion
Explanation:
Ionic bonds are generally positive and negative because one is gaining electrons while the other is losing.
NaOH is a hygroscopic compound, which means that it has a very strong affinity for water. Moreover, NaOH is also a stronger base than acetic acid is a strong acid. These two properties of NaOH make it necessary for different precautions to be taken while preparing a solution.
On the other hand, acetic acid is not very reactive and may easily be prepared in a solution of unboiled water.
Absolute zero that means cooling - 0 degree
