Question

reactiile care au loc la dizolvarea in apa :
H2SO4
NH3
H2O

PH-UL REACTIILOR
HCL 0,1 M
NAOH 0,3 M

Answer 1

H₂SO₄ + H₂O ⇄ HSO₄⁻ + H₃O⁺

NH₃ + H₂O ⇄ NH₄⁺ + OH⁻

H₂O + H₂O ⇆ H₃O⁺ + OH⁻

HCl, C = 0,1 M

HCl -> A.T => [HCl] = C = [H₃O⁺] = 10⁻pH = 10⁻¹ M => pH = 1

NaOH, C = 0,3M

[NaOH] = C = [OH⁻] = 10⁻pOH = 3*10⁻¹ M => pOH = 3*10⁻¹

Kw = [OH⁻]*[H₃O⁺] = 10⁻¹⁴ (mol/L)² ⇒ [H₃O⁺] = (10⁻¹⁴)/(3*10⁻¹) = 0,333*10⁻¹³ M

pH = -lg [ H₃O⁺] = -lg 0,333*10⁻¹³ = 13,477