Which of the following statements(s) about cyclohexane is/are correct?

A. Stability of different conformations of cyclohexane is Chair > Boat > Twist Boat > Half Chair
B. Only the chair form is free from angle strain.
C. Half chair has five C atoms in one plane and one C atom out of the plane. Hence, it has both eclipsing and bond angle strains and is the least stable conformer of cyclohexane.
D. Twisting the boat to the skew boat conformation moves the flagpole H atoms away from each other and reduces the eclipsing strain. Hence, the twist boat is more stable than the boat conformation.

Let's evaluate each statement:

A. "Stability of different conformations of cyclohexane is Chair > Boat > Twist Boat > Half Chair."
This statement is generally correct. The chair conformation is indeed the most stable, followed by the boat, twist boat, and half-chair conformations in that order.

B. "Only the chair form is free from angle strain."
This statement is correct. The chair conformation of cyclohexane is free from angle strain because all the bond angles in this conformation are very close to the ideal tetrahedral angle of 109.5 degrees.

C. "Half chair has five C atoms in one plane and one C atom out of the plane. Hence, it has both eclipsing and bond angle strains and is the least stable conformer of cyclohexane."
This statement is mostly correct. The half-chair conformation does indeed have both eclipsing and bond angle strains due to the non-planar arrangement of carbon atoms. It is generally considered less stable than the chair or boat conformations but more stable than the twist boat conformation.

D. "Twisting the boat to the skew boat conformation moves the flagpole H atoms away from each other and reduces the eclipsing strain. Hence, the twist boat is more stable than the boat conformation."
This statement is correct. Twisting the boat to the skew boat conformation does indeed reduce the eclipsing strain between the hydrogen atoms on the flagpole carbons, making it more stable than the traditional boat conformation.

In summary, statements A, B, C, and D are mostly correct, with some minor nuances.