Question

Hallar el pH, 2g de NaOH en H2O hasta un volumen de 250ml

Answer 1

Mm NaOH = 40 g/mol

1. Calcular la concentración: M = mol/V(L)

a) calcular moles de NaOH

n = 2 g / 40 g/mol
n = 0.05 moles

b) convertir mL a L
L = 250 / 1000 = 0.250 L

c) calcular la M

M = 0.05 mol / 0.250 L
M = 0.2 molar

d) calcular pOH

pOH = -log  [OH⁻]

pOH = -Log (0.2)

pOH = - ( -0.69) = 0.69 ≈ 0.70

2. Calcular pOH

pH  + pOH = 14

pOH = 14 - 0.7 = 13.3