Introduction:
The melting point of a solid is the temperature at which it changes from a solid to a liquid. It is dependent on the strength of the inter-particle forces between the particles of the solid. In this case, we are comparing the melting points of two solids, A and B, to determine which has stronger inter-particle forces.

Inter-particle forces:
Inter-particle forces are the attractive or repulsive forces between particles. In solids, the inter-particle forces are strong enough to hold the particles in a fixed position, giving the solid its shape and volume. The strength of these forces is determined by several factors, including the types of particles involved and the distance between them.

Comparison of melting points:
Solid A has a melting point of 300 K, while solid B has a melting point of 350 K. This means that solid B requires a higher temperature to melt than solid A, indicating that the inter-particle forces in solid B are stronger than in solid A.

Explanation:
The difference in melting points can be explained by the types of inter-particle forces present in each solid. Solid A may have weaker inter-particle forces, such as London dispersion forces or dipole-dipole forces, while solid B may have stronger inter-particle forces, such as hydrogen bonding or ion-dipole forces.

Hydrogen bonding is a particularly strong inter-particle force that occurs between molecules that contain hydrogen bonded to either oxygen, nitrogen, or fluorine. This force is responsible for the high melting points of substances such as water and ammonia. If solid B contains hydrogen bonding, it would explain why it has a higher melting point than solid A.

Ion-dipole forces occur between ions and polar molecules. This force is responsible for the high melting points of ionic compounds such as sodium chloride. If solid B contains ions, it would explain why it has a higher melting point than solid A.

Conclusion:
In conclusion, the melting point of a solid depends on the strength of the inter-particle forces between its particles. Solid B has a higher melting point than solid A, indicating that the inter-particle forces in solid B are stronger. The difference in melting points can be attributed to the types of inter-particle forces present in each solid, such as hydrogen bonding or ion-dipole forces.

300k = 26 •c and 350k = 77•c
so , the answer will be 350k , because it is requiring high kinetic energy (temperature) to break the bonds .