ANS:A - pressure

The correct statement is: "pressure." Normality (𝑁N) of a solution is defined as the number of equivalents of solute present in one liter of the solution. It is calculated using the formula: 𝑁=Number of equivalents of soluteVolume of solution in litersN=Volume of solution in litersNumber of equivalents of solute​ Pressure does not affect the number of equivalents of solute present in the solution, nor does it change the volume of the solution in liters. Therefore, the normality of a solution remains unchanged with an increase in pressure. The other options do affect the normality of a solution:

• Temperature: Changes in temperature can alter the volume of the solution, thus affecting the normality.
• Solute concentration: Increasing the solute concentration increases the number of equivalents of solute in the solution, thus altering the normality.
• Dilution of the solution: Dilution decreases the number of equivalents of solute per unit volume of the solution, thereby changing the normality.

Pressure is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. In simpler terms, pressure measures how much force is applied to a given area. It's a fundamental concept in physics and is crucial in various fields, including fluid dynamics, thermodynamics, and material science. Here are a few key points about pressure:

1. Definition: Pressure (𝑃P) is defined as the force (𝐹F) acting perpendicular to the surface of an object divided by the area (𝐴A) over which the force is applied. Mathematically, it's expressed as 𝑃=𝐹𝐴P=AF​.
2. Units: The SI unit of pressure is the Pascal (Pa), which is equivalent to one Newton per square meter (N/m2N/m2). Other common units include atmospheres (atm), millimeters of mercury (mmHg), and pounds per square inch (psi).
3. Effects of Pressure: Pressure can have various effects depending on the context. In fluid dynamics, pressure differences cause fluid flow, such as in the movement of air (wind) or water (rivers). In thermodynamics, pressure plays a crucial role in determining the behavior of gases and their phase transitions. In material science, pressure influences the mechanical properties of materials, such as their strength and deformation behavior.
4. Pressure in Gases: In gases, pressure arises due to the random motion of gas molecules colliding with the walls of the container. The force exerted by each collision and the frequency of collisions determine the pressure exerted by the gas.
5. Pressure in Liquids: In liquids, pressure arises from the weight of the liquid above a given point, as well as from external forces applied to the liquid's surface. Unlike gases, liquids are considered to be nearly incompressible, meaning their volume changes very little under pressure.
6. Hydrostatic Pressure: Hydrostatic pressure is the pressure exerted by a fluid at rest due to the force of gravity. It increases with depth below the surface of the fluid and is given by the equation 𝑃=𝜌⋅𝑔⋅ℎP=ρ⋅g⋅h, where 𝜌ρ is the density of the fluid, 𝑔g is the acceleration due to gravity, and ℎh is the depth.

Overall, pressure is a fundamental concept that describes the distribution of force over an area and has diverse applications across many scientific and engineering disciplines.