For 10: At which temp is sublimation impossible? Sublimation is the direct change of solid --> gas. So, you look at the phase diagram, and put a vertical line at the temperatures offered as choices. Which line doesn't directly cross the solid/gas boundary? That's your answer, because sublimation is a direct transition. Remember, 0 degrees = 273 K. You also have to be able to decide which area is gas, solid, liquid, since they aren't labeled. But it's a typical diagram, that shouldn't be an issue.
For 14: It is looking for a false statement, you're right. Answer A is a true statement, because in Figure 1, there is not a direct solid-->gas transition at 25 degrees, or 298 K. You have to cross the liquid phase to go between solid and gas. D is the false statement, it says, "For compound A (figure 1) there exists a solid less dense than its liquid phase." If that were true, you'd be able to draw a temperature line somewhere on the diagram, and while moving from low pressure to higher pressure, you would move from solid to liquid. By adding pressure, you would COMPRESS the solid to a liquid.
Water is the common example of this, and you can quickly recognize it's phase diagram because of the negative slope separating the liquid and solid phases. That negative slope means you can do that constant temperature, increasing pressure transition from solid to liquid.