I need help with this question!!

A. 15

Explanation:

From the equation we see that 6 water particles are used to make 1 particle of the hexose.

That means, that to make 1 mole of the hexose, we need 6 moles of water (as a mole is an unit of count of particles).

To make 2.5moles of the hexose, we need 2.5*6 moles of water, so 15 moles of water.

a electronegativity decreases beacuse the size of nucleus is bigger.