Explanation:
Sublimation is defined as a process in which solid state of a substance directly changes into vapor or gaseous state without undergoing liquid phase.
For example, naphthalene balls show sublimation at room temperature.
As this process does not cause any change in chemical composition of a substance. Hence, it is known as a physical process.
Similarly, when 
sublimes readily at 
. This shows change in physical state of carbon dioxide is taking place, i.e, from solid to gaseous phase.
Thus, we can conclude that when sublimes readily at then it means physical properties are usually associated with a compound that undergoes this kind of change.
Answer:
Double and triple covalent bonds occur when four or six electrons are shared between two atoms, and they are indicated in Lewis structures by drawing two or three lines connecting one atom to another
Explanation:
Answer : Carbon tetrachloride, 
will show the greatest freezing point lowering.
Explanation :
For non-electrolyte solution, the formula used for lowering in freezing point is,
where,
= lowering in freezing point
= molal depression constant
m = molality
As per question, the molality is same for all the non-electrolyte solution. So, the lowering in freezing point is depend on the only.
That means the higher the value of , the higher will be the freezing point lowering.
From the given non-electrolyte solutions, the value of of carbon tetrachloride is higher than the other solutions.
Therefore, Carbon tetrachloride, will show the greatest freezing point lowering.
Answer: The statement which could possibly not be true is C -" Liquid X can exist as a stable phase at 25°C, 1atm."
Explanation:
Triple point is the point where a substance co-exist as solid liquid and gas. At any point other than the triple point, the substance exist as a single phase substance.
As shown in the diagram, Liquid cannot exist as a stable phase at 1atm( below the the triple point pressure of 2atm) as the liquid can only exist beyond the pressure of triple point.
