Question

11) The pk, values of HCl and HI are - 7.0 and - 10.0 respectively. Which is stronger acid ?
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Answer 1

Answer:

The stronger acid among HCl and HI with $P_k_a$ values $-\ 7.0$ and $-\ 10.0$ is HI·

Explanation:

Given that,

The value of $P_k_a$ of HCl $=$ $-\ 7.0$

The value of $P_k_a$ of HI  $=$ $-\ 10.0$

The $P_k_a$ of an acid is defined as "the negative logarithm of an acid dissociation constant of a solution"·

That is,

$P_k_a\ =\ -\ log_1_0\ K_a$

Where $K_a$ is called the acid dissociation constant·

It is said that, $P_k_a$ is the measure of the strength of an acid·

Stronger acids will have got lower $P_k_a$ and weaker acids will have a really high $P_k_a$ value·

Here,

The acid HI has got less $P_k_a$ value which is $-\ 10.0$ and an acid HCl has got high $P_k_a$ value which is $-\ 7$· So the stronger acid here is HI·

Hence,

The stronger acid is HI·