Answer to Question #55368 in General Chemistry for Max

Question

Calculate the number of milliters of 0.582 M NaOH required to precipitate as Fe(OH)2 all of the Fe2+ ions in 110 mL of 0.451M FeCl2 solution.

Answer 1

Reaction:
Fe²⁺ + 2OH^- = Fe(OH)₂↓
So, n (NaOH) = 2n(Fe²⁺)
n (Fe²⁺) = V×c = 0.1 × 0.451 = 0.0451 (mol)
n (NaOH) = n (Fe²⁺) × 2 = 0.0451 × 2 = 0.0902 (mol)
c = n/V; V = n/c
V(NaOH) = 0.0902 / 0.582 = 0.155 (L)

Answer: V(NaOH) = 155 mL