Question

pOH of water is 7.0 at 298 K. If water is heated to 350 K, which of the following should be true ?

• A. pOH will decrease
• B. pOH will increase
• C. pOH will remain seven
• D. Concentration of $H^+$ ions will increase butthat of $OH^-$ will decrease

Answer 1

Answer: (A)

pOH will decrease

Answer 2

At $298\, K$, for pure water $pH = pOH = 7$. On increasing the temperature, the self ionisation of water increases thereby increasing the concentrations of $H_{3}O^{+}$ as well as $OH^{-}$ ions. Consequently, at high temperature, the $pH$ as well as $pOH$ will be $