Question

Parachors of two liquids can be compared by (a) their molar volumes (b) their molecular masses (c) their atomic numbers (d) their vapour pressure

Short answer

The correct option for comparing parachors of two liquids is (a) their molar volumes.

Step-by-step solution

Understand Parachor

The Parachor is a physical property of a substance related to its volume and surface tension. It allows predicting the latter from the volume of the substance.

Compare the given options

Given four options, molar volumes, molecular masses, atomic numbers, and vapour pressure, only one is directly connected to the concept of parachor.

Select the suitable property for comparison

None of molecular masses, atomic numbers, and vapour pressure have direct relationships with the volume and surface tension of the substance. However, the molar volumes, which is directly related to the volume of the substance, can be used to compare the parachors of two liquids.

Key concepts

Molar Volume

Molar volume is a crucial concept when discussing the properties of substances, particularly liquids. It refers to the volume occupied by one mole of a substance. Understanding molar volume helps us grasp how much space a specific amount of matter takes up, which is useful in various scientific contexts. Here's why molar volume matters in the context of parachors:

• It provides insight into the size or expansiveness of a liquid.
• Molar volume is directly related to both the molecular structure and the arrangement of atoms in a liquid.
• Differences in molar volumes between two liquids can influence their parachors.

By comparing the molar volumes of two substances, researchers can make educated estimates about how their surface tension might differ due to their structural and compositional characteristics. Molar volume, being directly connected to the volume aspect of parachor, can thus be a reliable measure in making such comparisons.

Surface Tension

Surface tension is a fascinating physical property playing a significant role in the behavior of liquids. It describes the elastic tendency of a liquid's surface, acting as if it were stretched by an invisible skin. This effect is due to the cohesive forces between liquid molecules. Here are some key points to understand about surface tension:

• It affects how liquids spread, how they drop, and how they interact with other materials.
• Surface tension has practical implications in scenarios like dropping liquids on different surfaces, forming bubbles, or when insects walk on water.
• It is closely tied with the molecule interaction, which means that the molecular composition will significantly impact the surface tension.

When considering parachors, the surface tension is crucial because parachor effectively uses surface tension measurements to relate to molar volume. Through understanding these two elements together, scientists can draw conclusions about the substance's overall behavior and compare different liquids.

Physical Property of Liquids

The physical properties of liquids, like parachors, are essential to comprehend how liquids interact with their environment and each other. These properties determine a liquid's behavior, stability, and usability in various applications. Key physical properties often include:

• Viscosity, which is the measure of a liquid's resistance to flow.
• Density, which affects buoyancy and layering of different liquids.
• Boiling and freezing points, which dictate the temperature conditions necessary for phase changes.

In relation to parachors, understanding the physical properties of liquids allows for a better comparison and contrast between different substances. Since parachor is derived from the molar volume and surface tension, it essentially captures a composite picture of these elemental properties. Evaluating the physical properties helps in predicting behaviors like spreading, absorption, and reacting under various conditions, making it an indispensable tool in material science and chemistry.