In the realm of environmental and water treatment, maintaining a balanced pH is crucial. This is especially true when dealing with acidic wastes, which can be harmful to both human health and the environment. To neutralize these acidic wastes, we often rely on alkaline reagents, such as sodium hydroxide (NaOH) or calcium hydroxide (Ca(OH)₂). However, not all alkaline reagents are created equal. This is where the basicity factor comes into play.
What is the Basicity Factor?
The basicity factor is a numerical value that quantifies the neutralizing capacity of an alkaline reagent. It essentially tells us how much acid a given amount of the reagent can neutralize.
How is it Calculated?
The basicity factor is calculated by dividing the molecular weight of the alkaline reagent by its equivalent weight. The equivalent weight is the weight of the reagent that can neutralize one mole of acid.
For example, let's consider sodium hydroxide (NaOH):
Therefore, the basicity factor of NaOH = 40/40 = 1
Why is the Basicity Factor Important?
The basicity factor is crucial for several reasons:
Example Applications:
Conclusion:
The basicity factor is a valuable tool for understanding and optimizing the neutralization of acidic wastes. By carefully considering the basicity factor of different alkaline reagents, we can ensure efficient and cost-effective treatment of acidic waste streams, ultimately contributing to environmental protection and public health.
Instructions: Choose the best answer for each question.
1. What does the basicity factor of an alkaline reagent represent?
a) The weight of the reagent needed to neutralize one mole of acid.
Incorrect. This describes the equivalent weight of the reagent, not the basicity factor.
b) The amount of acid a given amount of the reagent can neutralize.
Correct! The basicity factor quantifies the neutralizing capacity of an alkaline reagent.
c) The pH of the reagent solution.
Incorrect. The pH of a reagent solution is not directly related to its basicity factor.
d) The concentration of hydroxide ions in the reagent.
Incorrect. While hydroxide concentration is important, the basicity factor considers the reagent's molecular weight and equivalent weight.
2. How is the basicity factor calculated?
a) By multiplying the molecular weight by the equivalent weight.
Incorrect. The calculation involves division, not multiplication.
b) By dividing the molecular weight by the equivalent weight.
Correct! This is the formula for calculating the basicity factor.
c) By subtracting the equivalent weight from the molecular weight.
Incorrect. The calculation involves division, not subtraction.
d) By adding the molecular weight and the equivalent weight.
Incorrect. The calculation involves division, not addition.
3. Why is the basicity factor important for choosing the right alkaline reagent?
a) It helps determine the cost-effectiveness of different reagents.
Correct! A reagent with a higher basicity factor may require less volume for neutralization, potentially reducing costs.
b) It allows us to calculate the exact amount of reagent needed for a specific neutralization task.
Correct! The basicity factor is crucial for accurate dosing to achieve complete neutralization.
c) It helps us predict the environmental impact of using different reagents.
Partially correct. While the basicity factor influences neutralization efficiency, other factors like reagent toxicity also contribute to environmental impact.
d) All of the above.
Correct! The basicity factor plays a significant role in reagent selection, accurate dosing, and overall neutralization efficiency.
4. Which of the following alkaline reagents has a basicity factor of 1?
a) Calcium hydroxide (Ca(OH)₂)
Incorrect. Calcium hydroxide has a basicity factor of 2.
b) Sodium hydroxide (NaOH)
Correct! Sodium hydroxide has one hydroxide ion and its molecular weight equals its equivalent weight.
c) Calcium carbonate (CaCO₃)
Incorrect. Calcium carbonate has a basicity factor of 1.5.
d) Sodium carbonate (Na₂CO₃)
Incorrect. Sodium carbonate has a basicity factor of 2.
5. In which of the following applications is the basicity factor NOT directly involved?
a) Neutralizing acidic wastewater from a factory.
Incorrect. The basicity factor is crucial for selecting and dosing the appropriate alkaline reagent for wastewater treatment.
b) Adjusting the pH of soil for optimal plant growth.
Incorrect. The basicity factor is important for selecting and applying the correct amount of alkaline material for soil remediation.
c) Determining the concentration of a strong acid solution.
Correct! The basicity factor is relevant for neutralizing acids, not for determining their concentration.
d) Calculating the amount of lime needed to neutralize a specific volume of acidic waste.
Incorrect. The basicity factor is essential for determining the accurate amount of lime needed for neutralization.
Scenario: A company has 500 liters of acidic waste with a pH of 3. The company wants to neutralize the waste using sodium hydroxide (NaOH). The concentration of the NaOH solution is 10% (w/v) and its density is 1.1 g/mL.
Task: Calculate the volume of NaOH solution needed to neutralize the acidic waste, assuming the desired final pH is 7. You can use the following information:
Instructions: Show your calculations and provide the final answer with the correct unit.
Here's the step-by-step solution:
Calculate the mass of NaOH per liter of solution:
Calculate the molarity of the NaOH solution:
Calculate the moles of H+ ions in the acidic waste:
Calculate the volume of NaOH solution needed:
Convert the volume to milliliters:
Therefore, 200 mL of the 10% (w/v) NaOH solution is needed to neutralize the acidic waste.
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