A__is a large explosion of a collasping supergiant star which occurs when fusin stops.

...~ While this is happening, the core collapse is halted when it becomes neutron degenerate matter — a white dwarf on steroids, so to speak. This causes the infalling layers to rebound in a massive shock front that rips the star apart in the colossal explosion we call a supernova ~...

-Koko

Explanation:And when the helium ignites, the outer layers of the star are blown off in huge clouds of gas and dust. Once a star stabilizes after it forms, it spends most of its lifetime in a state of dynamic equilibrium. ... Once the star depletes the available hydrogen in the core, the fusion stops, and the star begins to collapse.

answer: -

reaction:

na + cl ⇌ nacl

balanced chemical equation:

na + 2cl ⇌ nacl2

sodium + clorine goes to form sodium chloride (table salt).

the product is nacl2.

and the reactants are na and cl.

(note: if you don’t know what ⇌ means, read below: -

⇌(double head arrow) means reversible reaction).