Question

The value of the ion product constant for water, $\left(K_w\right)$ at ${60}^{\circ }C$ is $9.6\times {10}^{-14}{M}^2$. What is the $\left[H_3{O}^{+}\right]$ of a neutral aqueous solution at ${60}^{\circ }C$ and the nature of an aqueous solution with a $pH=7.0$ at ${60}^{\circ }C$ are respectively?

• A. $3.1\times {10}^{-8},acidic$
• B. $3.1\times {10}^{-7},neutral$
• C. $3.1\times {10}^{-8},basic$
• D. $3.1\times {10}^{-7},basic$

Answer 1

Answer: (D)

$3.1\times {10}^{-7},basic$

As we know,
$K_w=\left[H^{+}\right]\left[O{H}^{-}\right];\left[H_3{O}^{+}\right]=\sqrt{K_w}=3.1\times {10}^{-7}$.

$pH=-log(3.1\times {10}^{-7})=6.5$

Neutral solution have pH < 7

So, the solution with pH= 7 will be basic in nature.