You visited us 1 times! Enjoying our articles? Unlock Full Access!

Characteristics of Equilibrium Constant

If the concen...

Question

If the concentration of ${O H}^{-}$ ions in the reaction:
$F e {(O H)}_{3} (s) ⇌ {F e}^{3 +} (a q) + 3 {O H}^{-} (a q .)$
is decreased by $1 / 4$ times, then equilibrium concentration of ${F e}^{3 +}$ will increase by:

64

times

Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses

4

times

No worries! We‘ve got your back. Try BYJU‘S free classes today!

8

times

No worries! We‘ve got your back. Try BYJU‘S free classes today!

16

times

No worries! We‘ve got your back. Try BYJU‘S free classes today!

Open in App

Solution

The correct option is A $64$ times
If the concentration of ${O H}^{-}$ ions in the reaction:
$F e {(O H)}_{3} (s) ⇌ {F e}^{3 +} (a q) + 3 {O H}^{-} (a q .)$
is decreased by $1 / 4$ times, then equilibrium concentration of ${F e}^{3 +}$ will increase by $64$ times.
$K = [{F e}^{3 +}]_{i} [{O H}^{-}]_{i}^{3}$ ....(1)
$K = [{F e}^{3 +}]_{f} [{O H}^{-}]_{f}^{3}$ ....(2)
$[{F e}^{3 +}]_{i}$ and $[{O H}^{-}]_{i}^{3}$ are the inital concentrations.
$[{F e}^{3 +}]_{f}$ and $[{O H}^{-}]_{f}^{3}$ are the final concentrations.
From (1) and (2)

$[{F e}^{3 +}]_{i} [{O H}^{-}]_{i}^{3} = [{F e}^{3 +}]_{f} [{O H}^{-}]_{f}^{3}$ .....(3)
The concentration of ${O H}^{-}$ ions is decreased by $1 / 4$ times
$[{O H}^{-}]_{f} = \frac{[{O H}^{-}]_{i}}{4}$ ....(4)
Substitute equation (4) in equation (3)
$[{F e}^{3 +}]_{i} [{O H}^{-}]_{i}^{3} = [{F e}^{3 +}]_{f} (\frac{[{O H}^{-}]_{i}}{4})^{3}$
$[{F e}^{3 +}]_{i} = [{F e}^{3 +}]_{f} (\frac{1}{4})^{3}$
$4^{3} \times [{F e}^{3 +}]_{i} = [{F e}^{3 +}]_{f}$
$64 \times [{F e}^{3 +}]_{i} = [{F e}^{3 +}]_{f}$

Suggest Corrections

Similar questions

O H^{-}

F e (O H)_{3} (s) ⇌ F e^{3 +} (a q) + 3 O H^{-} (a q)

1 / 4

F e^{3 +}

O H^{-}

F e (O H)_{3} (s) ⇋ F e^{3 +} + (a q) + 3 O H^{-} (a q)

1 / 4

F e^{3 +}

O H^{-}

F e (O H)_{3} (s) ⇋ F e^{3 +} + (a q) + 3 O H^{-} (a q)

1 / 4

F e^{3 +}

O H^{-}

F e (O H)_{3} (s) ⇌ F e^{+ 3} (a q .) + 3 O H^{-} (a q .)

\frac{1}{4}

F e^{+ 3}

F e {(O H)_{3}}_{(s)}

⇌ F e_{a q}^{3 +} + 3 O H_{a q}^{-}

O H^{-}

\frac{1}{4}

o f F e^{3 +}

Join BYJU'S Learning Program