JEE Main2010ChemistryChemical EquilibriumActual
In aqueous solution the ionization constants for carbonic acid are K ₁=4.2 10⁻⁷ and K ₂=4.8 10⁻¹¹ Select the correct statement for a saturated 0.034 M solution of the carbonic acid.
Options
- AThe concentration of CO ₃²⁻ is 0.034 M .
- BThe concentration of CO ₃²⁻ is greater than that of HCO ₃⁻ .
- CThe concentration of H ⁺ and HCO ₃⁻ are approximately equal.
- DThe concentration of H ⁺ is double that of CO ₃²⁻ .
Correct answer
C. The concentration of H ⁺ and HCO ₃⁻ are approximately equal.
Step-by-step solution
array lll A & H ₂ CO ₃ H ⁺+ HCO ₃⁻ & K ₁=4.2 10⁻⁷ ~B & HCO ₃⁻ H ⁺+ CO ₃⁻² & ~K ₂=4.8 10⁻¹¹ array As K ₂ K ₁ All major [ H ⁺ ]_ todal [ H ⁺ ]_ A and from I equilibrium, [ H ⁺ ]_ A [ HCO ₃⁻ ] [ H ⁺ ]_ tocal [ CO ₃⁻² ] is negligible compared to [ HCO ₃⁻ ] or [ H ⁺ ]_ total