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JEE MainChemistryIonic Equilibrium

A weak monoprotic acid solution has a concentration of 0.04 M and a measured pH of 3.0 . The acid dissociation constant ( K_a ) of the acid is x 10⁻⁶ . The value of x is ____.

Correct answer

25

Step-by-step solution

pH = 3.0 [ H ^+] = 10⁻³ M For a weak acid, [ H ^+] = K_a C K_a = [ H ^+]^2 C = (10⁻³)^2 0.04 = 10⁻⁶ 0.04 = 25 10⁻⁶ Thus, x = 25 . Answer: 25

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