(i) Melting point indicates the strength of forces of attraction between particles.
(ii) During melting, temperature of the solid remains constant until it has completely melted.
(iii) Boiling is a surface phenomenon.
(iv) Steam at 373 K has more energy than water at 373 K.
Analyzing Statements on States of Matter and Phase Transitions
This question requires us to evaluate the correctness of four different statements related to the physical properties of matter, specifically focusing on melting, boiling, and the energy involved in phase transitions.
Statement (i): Melting Point and Inter-particle Forces
The melting point is the temperature at which a substance changes state from solid to liquid. This transition occurs when the particles (atoms, ions, or molecules) gain enough kinetic energy to overcome the forces of attraction holding them in a fixed structure. A higher melting point signifies that stronger forces of attraction exist between the particles, requiring more energy to break them apart. Therefore, the melting point is indeed an indicator of the strength of these inter-particle forces. This statement is correct.
Statement (ii): Temperature During Melting
When a solid is heated, its temperature rises until it reaches its melting point. During the process of melting, the heat energy supplied is known as the latent heat of fusion. This energy is used to overcome the intermolecular forces holding the particles in the solid lattice, allowing them to move more freely in the liquid state. Importantly, the energy supplied does not increase the kinetic energy of the particles during this phase change, so the temperature remains constant until all the solid has melted. This statement is correct.
Statement (iii): Boiling as a Surface Phenomenon
Boiling is a bulk phenomenon that occurs when the vapor pressure of a liquid equals the ambient pressure. This causes vapor bubbles to form within the liquid and rise to the surface. In contrast, evaporation is a surface phenomenon where particles escape from the liquid surface into the gaseous phase, which can occur at temperatures below the boiling point. Since boiling involves bubble formation throughout the liquid, it is not solely a surface phenomenon. This statement is incorrect.
Statement (iv): Energy of Steam vs. Water at 373 K
The temperature $373$ K corresponds to $100$°C, which is the standard boiling point of water. At this temperature, water can exist as liquid water or as steam (gaseous water). To convert liquid water at $373$ K into steam at $373$ K, additional energy must be supplied. This energy is called the latent heat of vaporization. It is used to overcome the intermolecular attractive forces in the liquid state, allowing the molecules to separate and form a gas. Consequently, steam at $373$ K possesses more internal energy than liquid water at the same temperature ($373$ K). This statement is correct.
Conclusion
Based on the analysis, statements (i), (ii), and (iv) are correct, while statement (iii) is incorrect.
- Statement (i): Correct
- Statement (ii): Correct
- Statement (iii): Incorrect
- Statement (iv): Correct
Therefore, the correct option includes statements (i), (ii), and (iv) only.
Important Questions from Basic Concepts in Physics
$50 \ \Omega$, $50 \ \Omega$ and $100 \ \Omega$ resistors are connected in series in a circuit. They can be replaced with a single resistor of ______________in the circuit.
- Which of the following statements correctly describes the relationship among the incident ray, the refracted ray, and the normal at the point of incidence when light passes from one transparent medium to another?
- Given below are two statements. Select the correct answer from the options given for these statements.
Statement I: Particles of matter are continuously moving, that is, they possess what we call kinetic energy.
Statement II: With increase in temperature, the kinetic energy of the particles also increases. - Absolute refractive index of a medium is the ratio of the speed of light in __________ to the speed of light in __________.
- Which of the following is NOT true about the Universal Law of Gravitation?
