Look in the link below for a table of the most massive stars.
Within a binary star system, the most massive star is called the primary star, whereas the least massive star is called the secondary star. See related question.
The most massive star known is R136A1 - a rather disappointing name - has a temperature of about 53,000 degrees kelvin. Our Sun for comparison is a mere 5,778 degrees kelvin.
No. The most massive stars have the shortest lifespans.
It varies, depending on the stage of the star's development.
See related question
its not a massive or a dwarf star
A massive collapsed star is a dead star.
its a blue color
No. Only the most massive stars explode.
That is not yet known for sure. Most large galaxies have a supermassive black hole in their center. It is known how a massive star can convert to a black hole, but it is not currently known how such a black hole would acquire such a huge mass since its creation.
Eta Carinae is a massive and highly unstable star known as a Luminous Blue Variable (LBV). It is one of the most massive and brightest stars known in the Milky Way galaxy, and it is located in the Carina constellation.
The most massive main sequence stars are typically blue in color, due to their high surface temperatures. These stars are known as O-type stars and can be tens of times more massive than the Sun.