is the flash invincible

i heard that flash is invincble im a marvel guy but i wasnt sure if it was true

No he isn't to put it shortly.

No he could be taken out by batman if he let him punch him

Nope. You're thinking of battle forums Flash. Who's always blood-lust, and has no consequences for using his abilities and just has no restrictions.

No. Flash is Barry. Invincible is Mark.

Not even close.

Invincible? No. Fast? Yes. The Flash is almost like any other human, except for the fact that he is connected to something known as the Speed Force. I'll give you a brief quote from the Comic Vine Speed Force wiki page.

"The Speed Force is an energy source in the DC Universe generated by Barry Allen that lets speedsters travel at otherwise impossible speeds as well as do other nifty tricks without being hindered by physics."

As powerful as you may be, it is not impossible to sustain injury or even die if you are connected to the Speed Force, even with the added accelerated healing factor that comes with the Force.

I wouldn't say the Flash is immortal either. While time dilation (Theory of Relativity), Flash moving at or faster than the speed of light, and his incredible metabolism all may play a role at how he ages, he won't necessarily age slower or become immortal altogether. Here is an interesting question I found asked on the Science Fiction & Fantasy forums: http://scifi.stackexchange.com/questions/33325/does-flash-age-slower-because-of-his-ability-to-run-at-relativistic-speed that you may find interesting.

To simply answer your question, no, the Flash is not "immortal" in any way. But it sure is damn hard him.

Depends on the battle.

No he can't beat beings made of pure energy because they are intangible and doesn't have mass or molecules

no mass= no kinetic energy and no molecules= flash can't phase something that doesn't have molecules

This mean that neither speed steal, phasing or infinite mass punch can't work

Flash is still powerful enough to beat Hulk with easy

no. a couple punches from Superman would drop him but flash is fast enough to dodge them with ease

maybe

nah but he can beat theoretically beat some powerful beings going all out and avoiding getting hit