In a reaction vessel \(0.184 \mathrm{~g}\) of \(\mathrm{NaOH}\) is required to be added for completing the reaction. How many millilitre of \(0.150 \mathrm{M} \mathrm{NaOH}\) solution should be added for this requirement.

Understanding molarity is essential for preparing solutions in chemistry. Molarity is a measure of concentration that tells us how many moles of solute are present in a liter of solution. It is denoted as 'M' and the unit is mol/L.

Molarity is calculated using the formula:
\[ \text{Molarity} = \frac{\text{Number of moles of solute}}{\text{Volume of solution in liters}} \]
In practical scenarios, such as preparing a solution for a reaction, you'll need to rearrange the formula to solve for the required volume when you are given both the molarity and the amount of solute in moles:
\[ \text{Volume (L)} = \frac{\text{Moles of solute}}{\text{Molarity}} \]
For example, in the provided exercise, you're asked to calculate how many milliliters of a 0.150 M NaOH solution are needed to get 0.184 g of NaOH.

One of the fundamental concepts in chemistry is the mole concept, which helps to quantify the amount of matter. A mole corresponds to Avogadro's number (\(6.022 \times 10^{23}\) atoms, molecules, or ions), which is a constant that represents the number of particles in a mole of any substance.

The mole concept is linked with the molar mass of a substance, which is the mass in grams of one mole of that substance. The molar mass of an element is numerically equal to its atomic weight and for a compound, it's the sum of the atomic weights of its constituent elements.

To convert grams to moles, the formula used is:
\[ \text{Moles} = \frac{\text{Mass (g)}}{\text{Molar Mass (g/mol)}} \]
In the given exercise, first, the mass of NaOH (0.184 g) needs to be converted to moles before using it in the molarity calculation.

Conversions between different units of volume are commonly performed in laboratory work to ensure proper measurements. In stoichiometry problems, it's often necessary to convert between liters and milliliters because laboratory apparatus displays different measurement units.

The conversion between liters and milliliters is straightforward:
\[1 \text{ Liter} = 1000 \text{ Milliliters}\]
To convert from liters to milliliters, you multiply by 1000, and to convert from milliliters to liters, you divide by 1000.
\[ \text{Volume (mL)} = \text{Volume (L)} \times 1000 \]
\[ \text{Volume (L)} = \frac{\text{Volume (mL)}}{1000} \]
As a final step in our exercise example, the volume of NaOH solution calculated in liters was converted into milliliters to provide a practical measurement for the laboratory work.