Answer to Question #227392 in Chemistry for Sehveetrraa Kumar

Question

Magnesium hydroxide solid is added into 50 cm^3 of 1.5 mol dm^-3 nitric acid. The mixture is stirred until there is no more change observed. Calculate the mass of magnesium hydroxide needed to react completely with the nitric acid

Answer 1

Mg(OH)₂ + 2HNO₃ = Mg(NO₃)₂ + 2H₂O

According to the equation, n (HNO3) = 2 x n (Mg(OH)₂)

Cn = n / V

n (Mg(OH)₂) = 1.5 x 0.05 = 0.075 mol

n = m / M

m = n x M

M (Mg(OH)₂) = 58.3 g/mol

m (Mg(OH)₂) = 0.075 x 58.3 = 4.4 g