Ka for the ionisation of Fe3+ to Fe(OH)2+ and H⊕ is 6.5×10−3 what is the maximum pH value which could be used so that at least 95% of the total Fe3+ in a dilute solution exists as Fe3+ (write your answer to nearest integer)?
Open in App
Solution
Fe3++H2O⇌Fe(OH)2++H+;Kh=6.5×10−3 (1 - h) [H⊕]=Ch and Kh=C⋅h21−h and h=5100 Thus, 6.5×10−3=C×5×5×100100×100×95 ∴C=2.47M∴[H⊕]=2.47×5100 ∴pH=0.9083