How many gallons of 20% salt solution must be mixed with 4 gallons of 40% salt solution to make 25% salt solution?

If is the amount (gal) of the 20% solution to be used, then the mixture would have a total volume of gal. We want to end up with a 25% salt solution, so that

answer:

the position of equilibrium will shift to the left.

step-by-step explanation:

the general equation for the dissociation of a weak base is

b + h₂o   ⇌   bh⁺ + oh⁻

according to le châtelier's principle, when a stress is applied to a system at equilibrium, the system will respond in a way that tends to relieve the stress.

if you apply a stress by adding more bh⁺ or oh⁻,   the system will respond by moving in a direction that gets rid of the added ions.

the position of equilibrium will shift to the left, forming more of the undissociated base.