Answer:
2 — 1.6 mol·L⁻¹
Explanation:
1. Write the chemical equation for the reaction.
Ca(OH)₂ + 2HCl ⟶ CaCl₂ + 2H₂O
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2. Calculate the mass of Ca(OH)₂.
V = 100 mL
1000 mL of solution contain 30 g Ca(OH)₂ Calculate the mass of Ca(OH)₂
Mass of Ca(OH)₂ = 100 × 30/1000
Mass of Ca(OH)₂ = 3.00 g Ca(OH)₂
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3. Calculate the moles of Ca(OH)₂
1 mol Ca(OH)₂ = 74.09 g Calculate the moles of Ca(OH)₂
Moles of Ca(OH)₂ = 3.00 × 1/74.09
Moles of Ca(OH)₂ = 0.0405 mol Ca(OH)₂
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4. Calculate the moles of HCl
2 mol HCl ≡ 1 mol Ca(OH)₂ Calculate the moles of HCl
Moles of HCl = 0.0405 × 2/1
Moles of HCl = 0.0810 mol HCl
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5. Calculate the molar concentration of the HCl
c = n/V
V = 50 mL = 0.050 L Calculate the concentration
c = 0.0810/0.050
c = 1.6 mol·L⁻¹
