C2(H2SO4) = 90% V2(H2SO4) = 5 л C2(H2SO4) = 20% V1(H2So4) - ?

To find the volume of the concentrated sulfuric acid (H₂SO₄) required to make a diluted solution, we can use the concept of dilution, which can be expressed by the following equation:

\[ C_1V_1 = C_2V_2 \]

Where:

• \(C_1\) is the concentration of the concentrated solution (90%),
• \(V_1\) is the volume of the concentrated solution we need to find,
• \(C_2\) is the concentration of the diluted solution (20%),
• \(V_2\) is the volume of the diluted solution (5 L).

First, we'll convert the percentages to their decimals by dividing by 100:

• \(C_1 = 0.90\)
• \(C_2 = 0.20\)

Now we can substitute the values into the equation:

\[ 0.90 V_1 = 0.20 \times 5 \]

Calculating the right side:

\[ 0.20 \times 5 = 1 \]

Now we have:

\[ 0.90 V_1 = 1 \]

To find \(V_1\), we can rearrange the equation:

\[ V_1 = \frac{1}{0.90} \approx 1.111 \, \text{L} \]

Thus, the volume of the concentrated sulfuric acid needed to prepare 5 liters of a 20% solution is approximately 1.11 liters.