Sep . 19, 2024 09:29 Back to list

0.5 m naoh ph

Understanding the pH of 0.5% Sodium Hydroxide Solution

Sodium hydroxide (NaOH), commonly known as lye or caustic soda, is a strong base used widely in various industrial applications. When dissolved in water, NaOH dissociates completely into sodium (Na⁺) and hydroxide ions (OH⁻), leading to significant increases in pH. In an aqueous solution, the pH level indicates the concentration of hydrogen ions (H⁺) present, which is crucial for understanding the acidity or basicity of a solution.

A 0.5% solution of sodium hydroxide translates to 0.5 grams of NaOH in 100 milliliters of water. To calculate its pH, we first need to determine the concentration of hydroxide ions in the solution. The molar mass of NaOH is approximately 40 g/mol. Therefore, 0.5 g of NaOH corresponds to about 0.0125 moles (0.5 g / 40 g/mol). Given that we have 100 ml (0.1 liters) of solution, the molarity (M) of the NaOH solution can be calculated as follows

\[ \text{Molarity} = \frac{\text{moles of solute}}{\text{liters of solution}} = \frac{0.0125 \text{ moles}}{0.1 \text{ L}} = 0.125 \text{ M} \]

Sodium hydroxide is a strong base, meaning it completely dissociates in water. Therefore, the concentration of hydroxide ions (OH⁻) in the solution is also 0.125 M. To find the pOH of the solution, we use the following equation

\[ \text{pOH} = -\log[\text{OH}⁻] = -\log[0.125] \approx 0.903 \]

0.5 m naoh ph

Since the relationship between pH and pOH in aqueous solutions is expressed by the equation

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

we can rearrange this to find the pH

\[ \text{pH} = 14 - \text{pOH} = 14 - 0.903 \approx 13.097 \]

Thus, the pH of a 0.5% sodium hydroxide solution is approximately 13.1, indicating that this solution is highly basic.

Understanding the pH of sodium hydroxide solutions is critical for various scientific and industrial processes. High pH levels can affect chemical reactions, influence the solubility of substances, and impact the overall safety and handling of chemical materials. Therefore, it is essential to utilize appropriate safety measures when working with such strong bases, including personal protective equipment to prevent skin and eye contact. In summary, a 0.5% sodium hydroxide solution showcases the distinctive properties of strong bases, with a resultant pH indicative of its capability to significantly affect biochemical and chemical processes.

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