Question

Which of the following solutions would have the highest [H3O+]? Assume that they are all 0.10 M in acid at 25∘C. The acid is followed by its Ka value. C) HNO2, 4.6 × 10-4 B) HCN, 4.9 × 10-10 E) HClO2, 1.1 × 10-2 A) HF, 3.5 × 10-4 D) HCHO2, 1.8 × 10-4

Answer 1

Answer : The solution that has highest hydronium ion concentration is, (B) HCN, $4.9\times 10^{-10}$

Explanation :

As we know that:

$[H^+]=\sqrt{(K_aC)}$

And,

pH : It is defined as the negative logarithm of hydrogen ion or hydronium ion concentration.

$pH=-\log [H^+]$

From this we conclude that, as the value of $K_a$ (dissociation constant) increases then the value of hydrogen ion concentration also increases and the value of pH decreases.

That means, higher value of $K_a$ has lower pH and lower value of

Hence, the solution that has highest hydronium ion concentration is, (B) HCN, $4.9\times 10^{-10}$