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AP EAMCET · Chemistry · Chemical Equilibrium

(i) \(\mathrm{H}_3 \mathrm{PO}_4(a q) \rightleftharpoons \mathrm{H}^{+}(a q)+\mathrm{H}_2 \mathrm{PO}_4^{-}(a q)\)
(ii) \(\mathrm{H}_2 \mathrm{PO}_4^{-}(a q) \rightleftharpoons \mathrm{H}^{+}(a q)+\mathrm{HPO}_4^{2-}(a q)\)
(iii) \(\mathrm{HPO}_4^{2-}(a q) \rightleftharpoons \mathrm{H}^{+}(a q)+\mathrm{PO}_4^{3-}(a q)\)
The equilibrium constants for the above reactions at a certain temperature are \(K_1, K_2\) and \(K_3\) respectively. The equilibrium constant for the reaction \(\mathrm{H}_3 \mathrm{PO}_4(a q) \rightleftharpoons 3 \mathrm{H}^{+}(a q)+\mathrm{PO}_4^{3-}(a q)\) in terms of \(K_1, K_2\) and \(K_3\) is

  1. A \(K_1+K_2+K_3\)
  2. B \(\frac{K_1}{K_2+K_3}\)
  3. C \(\frac{K_3}{K_1 K_2}\)
  4. D \(K_1 K_2 K_3\)
Verified Solution

Answer & Solution

Correct Answer

(D) \(K_1 K_2 K_3\)

Step-by-step Solution

Detailed explanation

Required relation \(\begin{aligned} & \mathrm{H}_3 \mathrm{PO}_4(a q) \rightleftharpoons 3 \mathrm{H}^{+}(a q)+\mathrm{PO}_4^{3-}(a q) \\ & K=\frac{\left[\mathrm{H}^{+}\right]^3\left[\mathrm{PO}_4^{3-}\right]}{\left[\mathrm{H}_3 \mathrm{PO}_4\right]} \end{aligned}\) For reaction…