Question

At ${80}^{\circ }C$, distilled water has hydronium ion$\left(H_3{O}^{+}\right)$ concentration equal to $1\times {10}^{-6}mol/l$. The value of $K_w$ at this temperature would be:

• A. $1\times {10}^{-6}$
• B. $1\times {10}^{-12}$
• C. $1\times {10}^{-9}$
• D. $1\times {10}^{-14}$

Answer 1

Answer: (B)

$1\times {10}^{-12}$

The distilled water is neutral with equal concentrations of hydrogen ion and hydroxide ion.

Hence, $K_w=\left[H^{+}\right]\left[O{H}^{-}\right]$

$=1\times {10}^{-6}\times 1\times {10}^{-6}$

$=1\times {10}^{-12}$.

Hence, the correct option is $\text{B}$