Respuesta :

Answer:

pH = 4.179

Explanation:

  • 4HNO3 + 2NaBr → Br2 + 2NO2 + 2NaNO3 + 2H2O

∴ mass HNO3 = 3.15 g

∴ mass NaBr = 2.6 g

∴ Vsln = 755 L

∴ molar mass HNO3 = 63.01 g/mol

⇒ moles HNO3 = (3.15 g)*(mol/63.01 g) = 0.05 mol

⇒ [HNO3] = (0.05 mol)/(755 L) = 6.62 E-5 M

HNO3 is a strong acid:

  • HNO3 + H2O → H3O+  +  NO3-

∴ [HNO3] = [H3O+]

⇒ [H3O+]= 6.62 E-5 M

∴ pH = - Log [H3O+]

pH = - Log (6.62 E-5)

⇒ pH = 4.179