The purple crystalline solid potassium permanganate forms a purple solution when dissolved in water.

I believe the above is an example of a physical change
Physical changes alter the physical form of substances without changing their chemical identities. A physical change may involve changing the state of a substance, such as melting ice, or changing the shape or the size of the pieces in a sample. Other physical changes involve the formation of mixtures in which all of the components retain their chemical identifies, such as dissolving sugar in water. 

For cyclohexane compounds drawn in a chair conformation:   -axial bonds are vertical  -equatorial bonds are parallel to two bonds within the ring.  thus, as i assume the chair conformation is drawn:   -the x group is in an axial position, as are the five other vertical bonds.  -three axial bonds are on the top face of the ring  -the other three axial bonds are on the bottom face  the position of the second substituent on each ring carbon is equatorial.  gauche groups must be on an adjacent carbon such as carbon 6 and carbon 2, and also gauche groups are rotated by 60 degrees relative to each other.  drawing the newman projections for c1–c2 and c1–c6 aids in visualizing the groups that are gauche to the y group on c1.  click this link and watch some academic videos that may you more understand the topic 

It has to be b i hope this