AIIMS 2004 Chemistry Strength of Acids Assertion Reason Question
Assertion : HClO₄ is a stronger acid than HClO₃.
Reason : Oxidation state of Cl in HClO₄ is +8 and in HClO₃, +5.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
Correct Answer
Detailed Explanation
Greater the number of negative atoms present in the oxy-acid make the acid stronger. In general, the strengths of acids that have general formula, (HO)mZOn can be related to the value of n. As the value of n increases, acidic character also increases. The negative atoms draw electrons away from the Z-atom and make it more positive. The Z-atom, therefore, becomes more effective in withdrawing electron density away from the oxygen atom that bonded to hydrogen. In turn, the electrons of H – O bond are drawn more strongly away from the H-atom. The net effect makes it easier from the proton release and increases the acid strength.
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