Question

Which of the following oxyacid of chlorine has highest thermal stability?

• A. \(\mathrm{HClO_4}\)
• B. \(\mathrm{HClO}\)
• C. \(\mathrm{HClO_3}\)
• D. \(\mathrm{HClO_2}\)

Hint:

For oxyacids of the same element, higher oxidation state generally means higher thermal stability.

Answer 1

The Correct Option is A

Step 1: Recall stability trend of oxyacids.
The thermal stability of oxyacids of the same central atom increases with the increase in the oxidation state of the central atom and the number of oxygen atoms attached to it.

Step 2: Oxidation states of chlorine.
\(\mathrm{HClO}\): \(+1\)
\(\mathrm{HClO_2}\): \(+3\)
\(\mathrm{HClO_3}\): \(+5\)
\(\mathrm{HClO_4}\): \(+7\)

Step 3: Reason for highest stability.
In \(\mathrm{HClO_4}\), chlorine is in the highest oxidation state and the negative charge is most effectively delocalized over four oxygen atoms, giving maximum thermal stability.

Step 4: Conclusion.
Among the given oxyacids, \(\mathrm{HClO_4}\) is the most thermally stable.