The density of a 20.8% HNO3 solution is 1.12 g / ml. Determine the molar concentration of the acid.

univerkov | March 1, 2021 | education

Take 1 liter of acid solution:

Vp.-ra (HNO3) = 1 (l) = 1000 (ml).

Acid solution mass:

mr.-ra (HNO3) = pp.-ra (HNO3) * Vp.-ra (HNO3) = 1.12 * 1000 = 1120 (g).

Acid mass:

m (HNO3) = mr.-pa (HNO3) * w (HNO3) / 100 = 1120 * 20.8 / 100 = 232.96 (g).

Amount of acid substance:

v (HNO3) = m (HNO3) / M (HNO3) = 232.96 / 63 = 3.7 (mol).

Molar concentration of acid:

Cm (HNO3) = v (HNO3) / V (HNO3) = 3.7 / 1 = 3.7 (mol / L).

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