You want to determine the volume of a 2.5 M lithium nitrate solution needed to make 150 mL of a 1.0 M solution.

What is [tex]M_2[/tex] (molarity of the dilute solution) for this dilution?

Given:
- [tex]1.0 \, M[/tex]
- [tex]150 \, \text{mL}[/tex] of unknown [tex]LiNO_3[/tex]



Answer :

To solve this problem, we will use the concept of dilution, which is based on the principle of conservation of moles. In a dilution, the number of moles of solute remains the same before and after the dilution process, whereas the volume changes. The relationship can be described using the dilution formula:

[tex]\[ M_1 \times V_1 = M_2 \times V_2 \][/tex]

Where:
- [tex]\( M_1 \)[/tex] is the molarity of the concentrated solution.
- [tex]\( V_1 \)[/tex] is the volume of the concentrated solution needed.
- [tex]\( M_2 \)[/tex] is the molarity of the dilute solution.
- [tex]\( V_2 \)[/tex] is the volume of the dilute solution.

Given:
- [tex]\( M_1 = 2.5 \)[/tex] M (molarity of the concentrated lithium nitrate solution)
- [tex]\( V_1 = ? \)[/tex] (volume of the concentrated lithium nitrate solution we need to find)
- [tex]\( M_2 = 1.0 \)[/tex] M (molarity of the dilute lithium nitrate solution)
- [tex]\( V_2 = 150 \)[/tex] mL (volume of the dilute lithium nitrate solution)

We need to determine [tex]\( V_1 \)[/tex].

### Step-by-Step Solution

1. Write the dilution formula:

[tex]\[ M_1 \times V_1 = M_2 \times V_2 \][/tex]

2. Substitute the given values into the formula:

[tex]\[ 2.5 \times V_1 = 1.0 \times 150 \][/tex]

3. Solve for [tex]\( V_1 \)[/tex]:

[tex]\[ V_1 = \frac{1.0 \times 150}{2.5} \][/tex]

4. Calculate the value:

[tex]\[ V_1 = \frac{150}{2.5} \][/tex]

[tex]\[ V_1 = 60 \text{ mL} \][/tex]

### Conclusion
The volume of the 2.5 M lithium nitrate solution needed to make 150 mL of a 1.0 M solution is 60 mL.