# Problem: HF is a weak acid with Ka = 7.2 x 10-4What is the value of the equilibrium constant for the reaction:HF(aq) + OH-(aq) ⇌ H2O(λ) + F-(aq)A. 7.2 x 10-4B. 1.4 x 10-11C. 1.4 x 105D. 2.4 x 10-5E. 7.2 x 1010

###### FREE Expert Solution

We're being asked to write the equilibrium constant  for the following reaction:

HF(aq) + OH-(aq) ⇌ H2O(l) + F-(aq)

To determine the equilibrium constant, K, of the reaction equation, we’re going to use Hess’s Law. We’re going to manipulate some reactions with given K value to get the reaction equation with the unknown K

Recall the autoionization of water at 25°C:

H2O(l) ⇌ H+(aq) + OH-(aq)          Kw = 1.0x10-14

HF is a weak acid and it will partially dissociate in the solution:

HF ⇌ H+(aq) + F-(aq)                   Ka = 7.2x10-4

90% (453 ratings) ###### Problem Details

HF is a weak acid with Ka = 7.2 x 10-4

What is the value of the equilibrium constant for the reaction:

HF(aq) + OH-(aq) ⇌ H2O(λ) + F-(aq)

A. 7.2 x 10-4

B. 1.4 x 10-11

C. 1.4 x 105

D. 2.4 x 10-5

E. 7.2 x 1010

Frequently Asked Questions

What scientific concept do you need to know in order to solve this problem?

Our tutors have indicated that to solve this problem you will need to apply the Chemical Equilibrium concept. You can view video lessons to learn Chemical Equilibrium. Or if you need more Chemical Equilibrium practice, you can also practice Chemical Equilibrium practice problems.