substance having very high vapour pressure at its melting point, on heatingwill show

Explanation

High vapor pressure at the melting point indicates that the substance readily transitions from its solid phase to its vapor phase without passing through the liquid phase. This process is known as sublimation. When the substance is heated, it will directly convert from a solid to a vapor without melting into a liquid.Let's discuss why the other options might not apply:(a) Melting: If a substance has a very high vapor pressure at its melting point, it implies that the pressure of its vapor is quite significant even at that temperature. This would suggest that the substance tends to skip the liquid phase and directly transition from solid to vapor, rather than melting.(c) Decomposition: High vapor pressure at the melting point doesn't necessarily imply decomposition. While some substances might decompose at high temperatures, the focus here is on the behavior of the substance at its melting point.(d) Condensation: This process involves the transition from a vapor to a liquid upon cooling. However, in the scenario described (a substance with high vapor pressure at its melting point), the substance would likely bypass the liquid phase and undergo sublimation instead of condensation.