How many ml of concentrated (18M) of sulfuric acid H2SO4 are required to prepare 500 ml of 2M H2SO4
The Correct Answer and Explanation is :
To calculate the amount of concentrated sulfuric acid (18M) required to prepare 500 mL of 2M sulfuric acid solution, we use the dilution formula:
[
C_1V_1 = C_2V_2
]
Where:
- ( C_1 ) = concentration of the stock solution (18M)
- ( V_1 ) = volume of the stock solution to be used (in mL, what we need to find)
- ( C_2 ) = concentration of the diluted solution (2M)
- ( V_2 ) = volume of the diluted solution (500 mL)
Step 1: Rearrange the formula to solve for ( V_1 ):
[
V_1 = \frac{C_2V_2}{C_1}
]
Step 2: Plug in the known values:
[
V_1 = \frac{2 \, \text{M} \times 500 \, \text{mL}}{18 \, \text{M}}
]
Step 3: Perform the calculation:
[
V_1 = \frac{1000}{18} = 55.56 \, \text{mL}
]
Final Answer:
You need 55.56 mL of concentrated sulfuric acid (18M) to prepare 500 mL of 2M sulfuric acid solution.
Explanation:
The dilution equation ensures that the total number of moles of solute in the concentrated solution matches the total moles in the diluted solution. ( C_1 ) and ( C_2 ) represent molarity (moles of solute per liter), while ( V_1 ) and ( V_2 ) represent the respective volumes.
When diluting sulfuric acid, always add the acid to water, not the other way around. This prevents a violent exothermic reaction. In this calculation, ( V_1 ) (55.56 mL) represents the volume of 18M sulfuric acid to be carefully measured and added to enough water to reach a total volume of 500 mL.
This method ensures the desired molarity while maintaining safety and precision in preparing the solution.