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Phosphoric acid ionizes in three steps with their ionization constant values K_ a_1, ~K_ a_2 and K_ a_3, respectively, While K is the overall…

NEET UG 2025 — Chemistry Physical Chemistry

2025mcqmedium

Phosphoric acid ionizes in three steps with their ionization constant values Ka1, Ka2\mathrm{K}_{\mathrm{a}_1}, \mathrm{~K}_{\mathrm{a}_2}Ka1​​, Ka2​​ and Ka3\mathrm{K}_{\mathrm{a}_3}Ka3​​, respectively, While K is the overall ionization constant. Which of the following statements are true? A. log⁡K=log⁡Ka1+log⁡Ka2+log⁡Ka3\log \mathrm{K}=\log \mathrm{K}_{\mathrm{a}_1}+\log \mathrm{K}_{\mathrm{a}_2}+\log \mathrm{K}_{\mathrm{a}_3}logK=logKa1​​+logKa2​​+logKa3​​ B. H3PO4\mathrm{H}_3 \mathrm{PO}_4H3​PO4​ is a stronger acid than H2PO4−\mathrm{H}_2 \mathrm{PO}_4^{-}H2​PO4−​and HPO42−\mathrm{HPO}_4^{2-}HPO42−​ C. Ka1>Ka2>Ka3K_{a_1}\gt K_{a_2}\gt K_{a_3}Ka1​​>Ka2​​>Ka3​​ D. Ka1=Ka3+Ka22\mathrm{K}_{\mathrm{a}_1}=\frac{\mathrm{K}_{\mathrm{a}_3}+\mathrm{K}_{\mathrm{a}_2}}{2}Ka1​​=2Ka3​​+Ka2​​​ Choose the correct answer from the options given below:

Official previous-year question

Held on 30 Apr 2025 · Verified 9 Jul 2026.

Options

  1. A

    AAA and BBB only

  2. B

    AAA and CCC only

  3. C

    B,C and D only \mathrm{B}, \mathrm{C} \text { and } \mathrm{D} \text { only }B,C and D only 

  4. D

     A, B and C only \text { A, B and C only } A, B and C only 

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