Oct . 31, 2024 21:35 Back to list

Determining pH of 0.001M Sodium Hydroxide Solution in Chemistry实验

The pH of 0.001% NaOH Solution Understanding its Implications

Sodium hydroxide (NaOH), commonly known as lye or caustic soda, is a strong alkaline compound widely used in various industrial and laboratory applications. When dissolved in water, it dissociates completely into sodium (Na⁺) and hydroxide ions (OH⁻), resulting in a highly alkaline solution. One of the important aspects of sodium hydroxide solutions is their pH level, which indicates their acidity or alkalinity.

A 0.001% NaOH solution is a very dilute alkaline solution. To understand its pH, we first need to calculate the concentration of hydroxide ions in the solution. In a 0.001% w/v solution, there are 0.001 grams of NaOH in 100 milliliters of water. Given that the molar mass of NaOH is approximately 40 g/mol, the concentration of NaOH in moles per liter (M) is calculated as follows

\[ \text{Concentration (M)} = \frac{0.001 \text{ g}}{40 \text{ g/mol}} \times \frac{1000 \text{ mL}}{100 \text{ mL}} = 0.00025 \text{ M} \]

Since NaOH is a strong base that fully dissociates in water, the concentration of hydroxide ions [OH⁻] in the solution is also 0.00025 M. The pH of a solution can be calculated from the pOH, which is derived from the hydroxide ion concentration using the formula

\[ \text{pOH} = -\log[OH⁻] \]

Plugging in our value

\[ \text{pOH} = -\log(0.00025) \approx 3.60 \]

0.001 m naoh ph

Since pH and pOH are related through the equation

\[ \text{pH} + \text{pOH} = 14 \]

we can find the pH of our solution

\[ \text{pH} = 14 - \text{pOH} = 14 - 3.60 \approx 10.40 \]

This indicates that a 0.001% NaOH solution is indeed alkaline, but still much less basic than more concentrated solutions. The pH of 10.40 implies that while the solution has a higher concentration of hydroxide ions compared to neutral water (pH 7), it is far weaker compared to standard NaOH solutions, which can have a pH exceeding 13.

The relatively low pH value of this dilute solution suggests it can be used in applications where a mild base is required. In laboratory settings, such a dilute solution of NaOH can be employed in titrations, cleaning procedures, or as a buffering agent without introducing excessive alkalinity.

In conclusion, understanding the pH of a 0.001% NaOH solution helps to appreciate its practical applications and efficacy as a weak base. This low concentration facilitates safe handling and minimal reactivity while maintaining enough alkalinity for certain chemical reactions and processes. The analysis of such solutions is crucial in chemistry, providing a clear foundation for further studies in acid-base equilibria and interactions.

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