See related questions.
A neutron star or a pulsar, or a black hole.
No. A black hole will remain a black hole. A neutron star is a remnant of a star not massive enough to become a black hole.
It all relates to what you define as big. A black hole is an infinite region in space with an infinite density. It's "event horizon" is not infinite. If you wish to categorise between size of a neutron star and a black hole's "event horizon", then a black hole is, in most cases larger - but there are micro black holes, which exhibit all the characteristics of a black hole but have a much smaller "event horizon". In the physical sense, everything is bigger than a black hole, but in a terminological sense (the event horizon) it would depend on the mass of the black hole.
There's no mass range that's between "collapses into a neutron star or pulsar" and "collapses into a black hole". It'll be one or the other.
A black hole has more mass than a neutron star, but if you are comparing volume it would depend on the mass of the black hole. A neutron star is estimated to be about 14 miles in diameter, which is larger than the event horizon of a black hole up to about 3.8 times the mass of the sun. A more massive black hole will be larger.
the differece is a just like black hole and gutter hole.
When it turns into a black dwarf neutron star or black hole.
about 1/3 of a neutron star
after a neutron star collapses on itself
when a star dies
It all depends on mass. If its over the point of where a neutron star can form then it forms a black hole. If its below it then it'll form a neutron star.
They are all astronomical terms for stars or star related.