6.72 L of ammonia was passed through a solution containing sulfuric acid to form a medium salt. The mass of the resulting salt is

n (ammonia) = V / V  m = 6.72 / 22.4 = 0.3 mol
the number of moles of ammonium sulfate = half the number of moles of ammonia, which means
m (ammonium sulfate) = 0.5 * n (ammonia) * M = 19.8 g

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