The concentration of a solution may be defined as the amount of solute present in the given quantity of the solution.

The concentration of solution may be expressed in several ways as discussed below:

Mass Percentage

The mass percentage of a component in a given solution is the mass of the component per 100 g of the solution.

\[\text{Mass percentage of a component = }\frac{\text{Mass of the component in the solution}}{\text{Total mass of the solution}} × 100\]

Volume percentage

In the case of a liquid dissolved in another liquid, it is convenient to express the concentrations in volume percentage. The volume percentage is defined as the volume of the component per 100 parts by the volume of the solution.

Mass by volume percentage (w/v)

Sometimes, we express the concentrations as weight/volume. It is the mass of solute dissolved in 100 mL of the solution

Molarity of a solution

The molarity of a solution is defined as the number of moles of the solute dissolved per litre of the solution.It is represented as ′M′. Mathematically,

\[Molarity = \frac{\text{Moles of solute}}{\text{Volume of the solution (in mL)}} × 1000\]

Molarity of a solution

The molarity of a solution is defined as the number of moles of the solute dissolved per litre of the solution.

Molality of the solution

The molality of a solution is defined as the number of moles of the solute dissolved per 1000 g (or 1 kg) of the solvent.

The term ‘standard solution’ is used for the solution whose

All

The correct answer is option 4. All.

Let us understand in detail what a standard solution is and how it can have its normality, molarity, or strength known.

A standard solution is a solution of known concentration that is precisely prepared to be used in various chemical analyses, particularly in volumetric analysis and titrations. It serves as a reference or comparison solution to determine the concentration of an unknown substance or to carry out quantitative chemical reactions.

The concentration of a standard solution can be expressed in different ways:

1. Normality (N): Normality is defined as the number of equivalents of solute per liter of solution. It is used when dealing with acid-base reactions and redox reactions, where the number of equivalents of the solute is important. For example, if a solution contains 1 mole of a monoprotic acid (such as \(HCl)\), its normality would be 1 N because it furnishes 1 equivalent of \(H^+\) ions.

2. Molarity (M): Molarity is defined as the number of moles of solute per liter of solution. It is the most commonly used unit of concentration in chemistry. For example, if a solution contains 1 mole of a solute dissolved in 1 liter of the solution, its molarity would be 1 M.3.

Strength: Strength is a general term used to describe the concentration of a solution without specifying a particular unit. It can refer to normality, molarity, or other concentration units.

In practice, a standard solution is prepared by accurately weighing or measuring a known quantity of the pure solute and dissolving it in a measured volume of solvent (usually water) to obtain a precise concentration. The concentration is determined by carefully calculating the amount of solute and the volume of the solution.The preparation and use of standard solutions are crucial in analytical chemistry, where accurate and precise measurements are essential. By using standard solutions of known concentration, chemists can calibrate their instruments, perform titrations, and accurately determine the concentration of unknown substances in various samples.

In conclusion, a standard solution is a solution of known concentration that can have its normality, molarity, or strength known. It serves as a fundamental reference in chemical analysis and allows chemists to make precise and reliable measurements in their experiments.