Here's why:

* Water's Acidity: Water is a very weak acid, with a pKa of 15.7. This means it doesn't readily donate protons (H+ ions).

* Phenol's Acidity: Phenol is a weak acid, but it's a stronger acid than water, with a pKa of around 10. The phenyl ring (C6H5) attached to the hydroxyl group (-OH) stabilizes the phenoxide ion (C6H5O-) formed after losing a proton, making it more likely to donate a proton.

The lower the pKa value, the stronger the acid.

Therefore, since phenol has a lower pKa than water, it is a stronger acid.