Assuming 100% dissociation, calculate the freezing point and boiling point of 2.60 m k3po4(aq). constants may be found here.

 to find the freezing point, you use the following formula

fp solution= fp solvent - Δfp solution

fp solvent= 0 C (since the solvent was not stated, you can assume is water which freezing point is 0 degree celsius)

but first, we need to find the depression in freezing point (Δfp solution)

Δfp solution= Kf x i x m, where Kf is constant for the solvent, i is the number of particles produced by the solute and m is the molality of the solution.

Kf= 1.86 for water
i= 4 , becausethe solute breaks into 4 ions, K3PO4---> 3K+ + PO4-3
m= 2.60

Δfp solution= (1.86) (4) (2.60)= 19.3 C

fp solution= 0 - 19.3C= -19.3C


for boiling point, we use a similar formula and way to solve it. 

Δbp solution= bp solvent + Δbp solution

bp solvent= 100 C for water

to find the elevation boiling point (Δbp soln) is equal to:

Δbp solution= Kb x i x m

Kb= 0.512
i= 4
m= 2.60

Δbp solution= (0.512) (4) (2.60)= 5.32 C

bp solution= 100C + 5.32C= 105.32 C

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 

The answer is c) pyrite