Q.3.91 - An Introduction to General, Organic, and Biological Chemistry

Question

The melting point of dibromomethane is $-{53}^{o}C$ and its boiling point is ${97}^{o}C$. Sketch a heating curve for dibromomethane from $-{100}^{\circ }\mathrm{C}\text{ to }{120}^{\circ }\mathrm{C}$.

a. What is the state of dibromomethane at $-{75}^{\circ }\mathrm{C}$?

b. What happens on the curve at $-{53}^{\circ }\mathrm{C}$ ?

c. What is the state of dibromomethane at $-{18}^{\circ }\mathrm{C}$ ?

d. What is the state of dibromomethane at ${110}^{o}C$ ?

e. At what temperature will both solid and liquid be present? 

Step-by-Step Solution

Answer

a. dibromomethane is in solid-state

b. It will be parallel to the x-axis.

c. dibromomethane is in a liquid state

d. dibromomethane is in a gaseous state 

e. At $-{53}^{o}C$. Its melting point.

The graph is shown

Step 1: Given Information Part (a)

The melting point of dibromomethane = $-{53}^{o}C$

The boiling point of dibromomethane = ${97}^{o}C$

Step 2: Explanation Part (a)

Dibromomethane stays in solid structure till $-{53}^{o}C$ and starts to melt from this point onwards as it is the melting point.

Hence, dibromomethane is in solid-state at $-{75}^{\circ }\mathrm{C}$.

Step 3: Given Information Part (b)

The melting point of dibromomethane = $-{53}^{\circ }\mathrm{C}$

The boiling point of dibromomethane = ${97}^{o}C$

Step 4: Explanation Part (b)

At $-{53}^{\circ }\mathrm{C}$both the solid-state and liquid state co-exist as this is the melting point.

Step 5: Given Information Part (c)

The melting point of dibromomethane = $-{53}^{\circ }\mathrm{C}$

The boiling point of dibromomethane = ${97}^{o}C$

Step 6: Explanation Part (c)

dibromomethane remains in the liquid state from $-{53}^{\circ }\mathrm{C}\text{ to }{97}^{\circ }\mathrm{C}$.

Hence it will be in a liquid state at $-{18}^{\circ }\mathrm{C}$

Step 7: Given Information Part (d)

The melting point of dibromomethane = $-{53}^{\circ }\mathrm{C}$

The boiling point of dibromomethane = ${97}^{o}C$

Step 8: Explanation Part (d)

dibromomethane is in a gaseous state at ${97}^{o}C$ as it is the boiling point.

hence it will be in a gaseous state at ${110}^{o}C$.

Step 9: Given Information Part (e)

The melting point of dibromomethane = $-{53}^{o}C$

The boiling point of dibromomethane = ${97}^{o}C$

Step 10: Explanation Part (e)

At $-{53}^{o}C$ it will be in both solid and liquid states as this is the melting point. At the melting point, both the liquid and solid-state are present.

Step 11: Explanation

The graph is,