Chapter 16, Problem 3STP

Interpretation Introduction

Interpretation:

The segment of melting in the given curve needs to be determined.

Concept introduction:

The conversion of solid to liquid and gas involves the change in temperature that can display in heat curve.

The heating -cooling curve is the curve of temperature v/s time that interpret the change in the states of matter with increase in temperature. The phase diagram represents the change in the physical state of given substance with temperature and pressure.

Answer to Problem 3STP

Correct answer: Option B (segment BC) is correct answer.

Explanation of Solution

Reason for correct option: Melting point is the temperature at which solid melts to liquid whereas boiling point is the temperature at which liquid and gaseous state remain in equilibrium at 1 atm.

The point A indicates the solid state and at B it should start melting as there is a deflection point at B. The BC segment does not have any temperature change with time. It proves that the given energy is used to change the state of matter from solid to liquid that is called as melting. Thus the segment BC must show the melting.

Conclusion

Reasons for incorrect options: Other segments are after C therefore they must be after liquid state. The AB segment show increase in temperature with time so it is not interconversion of substance.