A : HClO4 is a stronger acid than HClO3 .R : Oxidation state of Cl in ...
Both assertion and reason are true but reason is not the correct explanation of assertion. 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)m ZOn 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 with drawing 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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A : HClO4 is a stronger acid than HClO3 .R : Oxidation state of Cl in ...
Assertion: HClO4 is a stronger acid than HClO3.
Reason: Oxidation state of Cl in HClO4 is 7 and in HClO3 is 5.
Explanation:
• The strength of an acid depends on its ability to donate a proton (H+). The more the acidic proton is attracted towards the anion, the stronger is the acid.
• In HClO4, the oxidation state of Cl is +7, which means Cl is more electronegative and attracts the bonded electrons towards itself. Therefore, the acidic proton is more attracted towards the anion (ClO4-) making it easier to donate the proton. Hence, HClO4 is a stronger acid than HClO3.
• In HClO3, the oxidation state of Cl is +5, which means Cl is less electronegative and attracts the bonded electrons towards itself to a lesser extent than in HClO4. Therefore, the acidic proton is less attracted towards the anion (ClO3-) making it more difficult to donate the proton. Hence, HClO3 is a weaker acid than HClO4.
• Therefore, both the assertion and reason are true. However, the reason is not the correct explanation of the assertion as the oxidation state of Cl is not the only factor that determines the strength of an acid. There are other factors such as the size and electronegativity of the atoms bonded to the acidic proton that also contribute to the acidic strength.
• Hence, the correct answer is option B - both assertion and reason are true but reason is not the correct explanation of the assertion.
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