The volume of the cylinder would be doubled.
The base areas quadruple and the curved surface doubles.
The diameter of a circle is doubled if the circumference is doubled.
It doubles The volume of a cylinder height times diameter squared times 3.14
The circumference is doubled or tripled, respectively.
If the altitude is not changed, the area would be doubled.
When the diameter is doubled, perhaps? Then the area is 4 x larger.
The surface area of the 'wall' doubles, but the base areas remain the same.
The volume is doubled.
If you double the circumference. the diameter like wise would double.