Mutualism! The tree provides a home and food for the ants, while the ants protect the tree :)
In a chemical reaction, the equilibrium constant refers to the value of its reaction quotient at chemical equilibrium, that is, a condition attained by a dynamic chemical system after adequate time has passed, and at which its composition has no measurable capacity to undergo any kind of further modification.
The given reaction is: HCN (aq) + OH⁻ = CN⁻ (aq) + H2O (l)
The equilibrium constant = product of concentration of products / product of concentration of reactants
(Here, H2O is not considered as its concentration is very high)
So, Keq = [CN⁻] / [HCN] [OH⁻]
A weak Bronsted-Lowry base is a weak proton acceptor, where the proton is in the form of H+, so the conjugate acid formed contains one more H atom and an extra positive charge.
Hope this helps!
I'd say that the answer is erosion