The reaction between HCl and Ba(OH)₂ is:
2HCl + Ba(OH)₂ → BaCl₂ + 2H₂O
Moles of Ba(OH)₂ used: n = 0.1 M × 0.025 L = 0.0025 mol
From stoichiometry: moles of HCl = 2 × 0.0025 = 0.005 mol
Mass of HCl = 0.005 mol × 36.5 g/mol = 0.1825 g = 182.5 mg
Expressing as x = ___ × 10⁻¹:
182.5 = 1825 × 10⁻¹
The numerical value is 1825 (or 1.825 × 10² mg when expressed with standard scientific notation)