Hydrochloric acid with a mass fraction of hydrogen chloride of 20% reacted in one case with methylamine

| May 25, 2021 | education

Hydrochloric acid with a mass fraction of hydrogen chloride of 20% reacted in one case with methylamine weighing 8.68 g, and in the other with aniline weighing 26.04 g. What is the weight ratio of the hydrochloric acid solutions taken for these reactions with amines?

1. Let’s find the amount of substance СН3NH2.

M (CH3NH2) = 31 g / mol.

n = 8.68 g: 31 g / mol = 0.28 mol.

Let’s find the quantitative ratios of substances.

CH3NH2 + HCl = CH3NH3Cl.

For 1 mol of CH3NH2, there is 1 mol of HCl. The substances are in quantitative ratios of 1: 1. The amount of the substance is equal.

n (HCl) = n (CH3NH2) = 0.28 mol.

Find the mass of HCl.

M (HCl) = 36.5 g / mol.

m = nM.

m = 0.28 mol × 36.5 g / mol = 10.22 g.

m (solution) = m (substance): W) × 100%.

m (solution) 1 = (10.22 g: 20%) × 100% = 51.1 g.

C6H5NH2 + HCl = C6H5NH3Cl.

Let’s find the amount of substance С6Н5NH2.

M (C6H5NH2) = 93 g / mol.

n = 26.04 g: 93 g / mol = 0.28 mol.

n (HCl) = n (C6H5NH2) = 0.28 mol.

m (solution) 2 = (10.22 g: 20%) × 100% = 51.1 g.

m (solution) 1: m (solution) 2 = 51.1 g: 51.1 g = 1: 1.



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