What mass of magnesium (GFM 24) reacts completely with 100 cm³ of 1.0 mol/l hydrochloric acid in Mg + 2HCl → MgCl₂ + H₂?
Answer and explanation
Correct answer: D. 1.2 g
- Step 1: Moles of HCl = 1.0 × 0.100 = 0.10 mol.
- Step 2: The ratio Mg : HCl is 1 : 2, so moles of Mg = 0.05 mol.
- Step 3: Mass = 0.05 × 24 = 1.2 g.
Answer
1.2 g.
Why not the others: 2.4 g: the 1 : 2 ratio was ignored. 0.05 g: the moles were not converted to mass. 24 g: this is the mass of 1 mol.
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