Calculate the mass fraction of nitric acid in the solution if it is known that 200 g

| September 1, 2021 | education

Calculate the mass fraction of nitric acid in the solution if it is known that 200 g of this solution has completely reacted with 4 g of potassium hydroxide.

1. The interaction of nitric acid with potassium hydroxide is described by the equation:

HNO3 + KOH = KNO3 + H2O.

2. Find the chemical amount of potassium hydroxide:

n (KOH) = m (KOH): M (KOH);

M (KOH) = 39 + 16 + 1 = 56 g / mol;

n (KOH) = 4: 56 = 0.0714 mol.

3. Set the amount of nitric acid:

n (HNO3) = n (KOH) = 0.0714 mol.

4. Calculate the mass of nitric acid:

m (HNO3) = n (HNO3) * M (HNO3);

M (HNO3) = 1 + 14 + 3 * 16 = 63 g / mol;

m (HNO3) = 0.0714 * 63 = 4.5 g.

5. Let’s calculate the mass fraction of nitric acid in the solution:

w (HNO3) = m (HNO3): mr-pa (HNO3) = 4.5: 200 = 0.0225 or 2.25%.

Answer: 2.25%.



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