# How many grams of a nitric acid solution with a mass fraction of HNO3

September 30, 2021 | education

| **How many grams of a nitric acid solution with a mass fraction of HNO3 of 20% is required to neutralize a solution containing KOH, weighing 5.6 g**

Given:

w% (HNO3) = 20%

m (KOH) = 5.6g

Find: m (HNO3) -?

Solution:

1) Reaction equation:

HNO3 + KOH = KNO3 + H2O

2) Find the amount of KOH that has reacted:

n (KOH) = m: M = 5.6 g: 56 g / mol = 0.1 mol

3) We compose a logical expression:

If 1 mol of HNO3 requires 1 mol of KOH,

then x mol HNO3 requires 0.1 mol KOH,

then x = 0.1 mol HNO3.

4) Find the mass of nitric acid in solution:

m (HNO3) = n * M = 0.1 mol * 63 g / mol = 6.3 g HNO3

5) Find the mass of the acid solution that has reacted, based on its concentration:

m (solution HNO3) = 6.3 g: 0.2 = 31.5 g.

Answer: m (solution HNO3) = 31.5 g.

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