Which change of state involves a release of energy? boiling condensation melting sublimation

Answer

Condensation

Explanation

Condensation is the change of the physical state of matter from gas phase into liquid phase, and is the reverse of vaporization.  When gas condenses to liquid the quantity of energy converted from chemical to heat is called the Heat of Vaporization or ΔHvap. As the gas particles cool down the particles slow down, and a liquid forms. For example, the droplets of water seen on a mirror when you exhale come from water vapor (in your breather) that cools enough to condense and collect on the mirror.

While in case of other three process boiling, melting and sublimation heat is required. They are endothermic process.

nacl or sodium chloride is an ionic compound. this is because an ionic compound pertains to a compound that consists of positively and negatively charged ions. in this case, na (sodium) has a tendency to lose one electron when it reacts with with other atoms, so the resulting sodium ion contains 11 protons and 10 electrons, thus making it positively charged (na+), when chlorine reacts, it usually gains one electron to form an ion called chloride, thus making it negatively charged ( since the ions are oppositely charged, they attract.