Which of the following statements are true? (a) The critical temperature must be re...

Which of the following statements are true?

(a) The critical temperature must be reached to change liquid to gas.

(b) To melt a solid at constant pressure, the temperature must be above the triple point.

(c) CHF₃ can be expected to have a higher boiling point than CHCl₃ because CHF₃ has hydrogen bonding.

(d) One metal crystallizes in a body-centered cubic cell and another in a face-centered cubic cell of the same volume. The two atomic radii are related by the factor