Question

Какой объём раствора гидроксида натрия с массовой долей NaOH 25% и плотностью 1,27 г/мл потребуется для нейтрализации раствора серой кислоты объёмом 500 мл с молярной концентрацией H2SO4 0,25 моль/л.

Answer 1

Решение задачи в фото ниже..

Answer 2

Calculating the Volume of Sodium Hydroxide Solution Needed

To calculate the volume of sodium hydroxide solution needed to neutralize the sulfuric acid solution, we can use the following steps:

1. Calculate the moles of sulfuric acid in the given volume. 2. Use the stoichiometry of the neutralization reaction to determine the moles of sodium hydroxide required. 3. Convert the moles of sodium hydroxide to volume using its molar concentration.

Step 1: Calculate the Moles of Sulfuric Acid

The molar concentration of sulfuric acid is given as 0.25 mol/L, and the volume is 500 mL. We can calculate the moles of sulfuric acid using the formula:

moles = molar concentration × volume (in liters)

Calculating the moles of sulfuric acid: ``` moles of H2SO4 = 0.25 mol/L × 0.5 L = 0.125 moles ```

Step 2: Determine the Moles of Sodium Hydroxide Required

The balanced chemical equation for the neutralization reaction between sulfuric acid (H2SO4) and sodium hydroxide (NaOH) is: ``` H2SO4 + 2NaOH → Na2SO4 + 2H2O ``` From the equation, we can see that 1 mole of sulfuric acid reacts with 2 moles of sodium hydroxide.

Therefore, the moles of sodium hydroxide required will be twice the moles of sulfuric acid: ``` moles of NaOH = 2 × moles of H2SO4 = 2 × 0.125 moles = 0.25 moles ```

Step 3: Convert Moles of Sodium Hydroxide to Volume

The molar concentration of the sodium hydroxide solution is not provided directly. However, we can use the mass percent and density of the solution to calculate the molar concentration and then convert the moles to volume.

Given: - Mass percent of NaOH = 25% - Density of the solution = 1.27 g/mL

First, we need to calculate the molar mass of NaOH: ``` Molar mass of NaOH = 22.99 g/mol (Na) + 15.999 g/mol (O) + 1.008 g/mol (H) = 39.997 g/mol ≈ 40 g/mol ```

Next, we can calculate the molarity of the NaOH solution using the mass percent and density: ``` Molarity (M) = (mass percent / molar mass) / (density in g/mL) Molarity (M) = (25 / 100) / (40 / 1.27) = 0.79375 mol/L ```

Finally, we can convert the moles of NaOH to volume using its molar concentration: ``` Volume of NaOH = moles / molarity = 0.25 moles / 0.79375 mol/L ≈ 0.3147 L ≈ 314.7 mL ```

Therefore, approximately 314.7 mL of the sodium hydroxide solution with a mass percent of 25% and a density of 1.27 g/mL will be needed to neutralize the 500 mL sulfuric acid solution with a molar concentration of 0.25 mol/L.