Yes you do
They require a tanker endorsement, and most commodities they haul also require the driver to have a hazmat endorsement.
You would need the N (tanker) and H (hazmat) endorsements. Most states issue an X endorsement as a combination of N and H.
Yes. You need a CDL and a hazmat endorsement both. You're well above the allotted amount which can be transported without the tanker and hazmat endorsements.
Yes. If it requires a tanker with an unrestricted CDL, so it does with a permit, as well.
N
Yes. No differentiation is made between liquid and dry bulk tankers in this regard.
Yes, and you would need hazmat and tanker endorsements, as well.
You will need a Class B CDL with tanker endorsement.
To answer you we need to know what country's traffic regulations you are asking about.
Yes. Tank trucks require a tanker endorsement, and the tanker endorsement can only be put onto a CDL. A permanently mounted tank requires one (the regs don't specify a minimum capacity), as do portable tanks of more than 1000 gallons.
Any tank vehicles, or anything defined as a portable tank with a capacity of greater than 1000 gallons.
Yes. You'll need the CDL of a class appropriate to the vehicle being operated, a tanker endorsement, and a hazmat endorsement. 300 gallons puts you well past the 1000 lb. threshold for not needing one.