The figure given above shows the temperature (T) - time (t) plot when we start heating a piece of naphthalene. The temperature (T) at the plateau of the curve signifies

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Q: 10 (NDA-II/2013)
The figure given above shows the temperature (T) - time (t) plot when we start heating a piece of naphthalene. The temperature (T) at the plateau of the curve signifies

question_subject: 

Science

question_exam: 

NDA-II

stats: 

0,1,8,1,4,1,3

keywords: 

{'boiling point': [0, 0, 0, 3], 'temperature': [0, 1, 1, 7], 'naphthalene': [0, 0, 0, 3], 'curve signifies': [0, 0, 0, 1], 'heating': [0, 1, 0, 0], 'plot': [0, 0, 1, 4], 'plateau': [3, 0, 1, 0], 'time': [2, 6, 15, 23], 'chemical change': [0, 0, 3, 7]}

The given temperature-time plot represents the change in temperature of a piece of naphthalene as it is being heated. It shows a curve that has a plateau or flat region. This plateau indicates that the temperature remains constant during this period, signifying a phase change.

Option 1 states that the plateau signifies the boiling point of naphthalene. However, the boiling point is the temperature at which a substance changes from a liquid to a gas. In the given plot, there is no indication of the naphthalene reaching its boiling point.

Option 2 suggests that the plateau represents the freezing point of naphthalene. However, the freezing point is the temperature at which a substance changes from a liquid to a solid. Again, there is no indication of the naphthalene reaching its freezing point in the given plot.

Option 3 correctly states that the plateau represents the melting point of naphthalene. The melting point is the temperature at which a substance changes from a solid to a liquid. The fact that the temperature remains constant during this plateau indicates that the naphthalene is undergoing a phase change from solid to liquid.

Option 4 suggests that the temperature at the plateau represents a chemical change upon heating. However, there is no information