Dissociation of benzoic acid Benzoic acid is a weak acid, so it does not completely dissociate in water. I know that the dissociation equation of benzoic acid is:

$$\ce{C6H5CO2H &lt;=&gt; H+ + C6H5CO2-}$$

The question I'm having trouble with is: 


  Would the dissociated form be more or less likely to dissolve in water?


Is this basically asking if the ions on the right are more likely to dissolve when compared to $\ce{C6H5CO2H}$? 

If this is what the question is asking, I think yes, the dissociated form will be more likely to dissolve as they are very polar when compared to $\ce{C6H5CO2H}$ and they can be surrounded by polar water molecules. But I'm not sure.
Solubility of benzoic acid(mw 122.12):


1.7 g/L (0 °C) - 0.00139 moles/100 ml
2.7 g/L (18 °C)
3.44 g/L (25 °C)
5.51 g/L (40 °C)
21.45 g/L (75 °C)
56.31 g/L (100 °C) - 0.04611 moles/100 ml


Solubility of sodium benzoate (mw 144.10):


62.69 g/100 mL (0 °C) - 0.4350 moles/100 ml
62.78 g/100 mL (15 °C)
62.87 g/100 mL (30 °C)
71.11 g/100 mL (100 °C) - 0.4935 moles/100 ml


So yes, sodium benzoate is more soluble than benzoic acid, but consider calcium benzoate which is less soluble. 

Calcium benzoate (mw 282.31):


2.32 g/100 mL (0 °C) - 0.00822 moles/100 ml
2.72 g/100 mL (20 °C)
8.7 g/100 mL (100 °C) - 0.03081 moles/100 ml


So the "real" answer is - it depends...