Question

At $25{}^{\circ }C$, water is neutral and has a $pH$ of $7$. If the temperature of water is increased to $60{}^{\circ }C$ then:

• A. It becomes acidic
• B. It becomes basic
• C. It remains neutral with $pH7$
• D. It remains neutral with $pH<7$

Answer 1

The correct option is D It remains neutral with $pH<7$

The dissociation of water is an endothermic process. Increasing the temperature increases the equilibrium constant value which causes the formation of more $H^{+}$ and $O{H}^{-}$ ions. But, the concentration of both ions are still equal. So, the solution is still neutral but the $pH$ decreases since the concentrations increase.