citric-acid-hoc-cooh-ch2cooh-2-is-a-weak-triprotic-acid-write-equations-that-sho

Question

Citric acid (HOC($$CO_{2}H$$)($$CH_{2}$CO_{2}H$$)_{2}) is a weak triprotic acid. Write balanced dissociation equations and corresponding equilibrium expressions for each dissociation step.

Accepted Answer

First Dissociation HOC(COOH)($$CH_{2}$$COOH)_{2}(aq) + $$H_{2}O(l$$) ⇌ $$H_{3}O$$^{+}$$(aq) + HOC(COO)(CH$$_{2}$$COOH)_{2}^{−}(aq) K_{a1} = [H$$_{3}$$O^{+}$$][HOC(COO)($$CH_{2}$$COOH)_{2}^{−}]/[HOC(COOH)($$CH_{2}$$COOH)_{2}]  Second dissociation HOC(COO)($$CH_{2}$$COOH)_{2}^{−}(aq) + $$H_{2}O(l$$) ⇌ $$H_{3}O$$^{+}$$(aq) + [HOC(COO)(CH$$_{2}$$COO)(CH$$_{2}$$COOH)]^{2−}(aq) K_{a2} = [H$$_{3}$$O^{+}$$][HOC(COO)($$CH_{2}$$COO)($$CH_{2}$$COOH)^{2−}$$]/[HOC(COO)(CH$$_{2}$$COOH)_{2}^{−}]  Third dissociation [HOC(COO)(CH$$_{2}$$COO)(CH$$_{2}$$COOH)]^{2−}(aq) + H$$_{2}$$O(l) ⇌ H$$_{3}$$O^{+}(aq$$) + [HOC(COO)($$CH_{2}$$COO)_{2}]^{3−}(aq) K_{a3} = [$$H_{3}O$$^{+}$$][HOC(COO)(CH$$_{2}$$COO)_{2}]^{3−}]/[HOC(COO)(CH$$_{2}$$COO)(CH$$_{2}$$COOH)^{2−}$$]

Answer

First Dissociation HOC(COOH)($$CH_{2}$$COOH)_{2}(aq) + $$H_{2}O(l$$) ⇌ $$H_{3}O$$^{+}$$(aq) + HOC(COO)(CH$$_{2}$$COOH)_{2}^{2−}(aq) K_{a1} = [H$$_{3}$$O^{+}$$][HOC(COO)($$CH_{2}$$COOH)_{2}^{2−}]/[HOC(COOH)($$CH_{2}$$COOH)_{2}]  Second dissociation HOC(COO)($$CH_{2}$$COOH)_{2}^{−}(aq) + $$H_{2}O(l$$) ⇌ $$H_{3}O$$^{+}$$(aq) + [HOC(COO)(CH$$_{2}$$COO)(CH$$_{2}$$COOH)]^{2−}(aq) K_{a2} = [H$$_{3}$$O^{+}$$][HOC(COO)($$CH_{2}$$COO)($$CH_{2}$$COOH)^{2−}$$]/[HOC(COO)(CH$$_{2}$$COOH)_{2}^{−}]  Third dissociation [HOC(COO)(CH$$_{2}$$COO)(CH$$_{2}$$COOH)]^{2−}(aq) + H$$_{2}$$O(l) ⇌ H$$_{3}$$O^{+}(aq$$) + [HOC(COO)($$CH_{2}$$COO)_{2}]^{3−}(aq) K_{a3} = [$$H_{3}O$$^{+}$$][HOC(COO)(CH$$_{2}$$COO)_{2}]^{3−}]/[HOC(COO)(CH$$_{2}$$COO)(CH$$_{2}$$COOH)^{2−}$$]

Answer

First Dissociation HOC(COOH)($$CH_{2}$$COOH)_{2}(aq) + $$H_{2}O(l$$) ⇌ $$H_{3}O$$^{+}$$(aq) + HOC(COO)(CH$$_{2}$$COOH)_{2}^{−}(aq) K_{a1} = [H$$_{3}$$O^{+}$$][HOC(COO)($$CH_{2}$$COOH)_{2}^{−}]/[HOC(COOH)($$CH_{2}$$COOH)_{2}]  Second dissociation HOC(COO)($$CH_{2}$$COOH)_{2}^{−}(aq) + $$H_{2}O(l$$) ⇌ $$H_{3}O$$^{+}$$(aq) + [HOC(COO)(CH$$_{2}$$COO)(CH$$_{2}$$COOH)]^{2−}(aq) K_{a2} = [H$$_{3}$$O^{+}$$][HOC(COO)($$CH_{2}$$COOH)_{2}^{−}]/[HOC(COO)($$CH_{2}$$COO)($$CH_{2}$$COOH)^{2−}$$]  Third dissociation [HOC(COO)(CH$$_{2}$$COO)(CH$$_{2}$$COOH)]_{2}^{−}(aq) + H$$_{2}$$O(l) ⇌ H$$_{3}$$O^{+}(aq$$) + [HOC(COO)($$CH_{2}$$COO)_{2}]^{3−}(aq) K_{a3} = [$$H_{3}O$$^{+}$$][HOC(COO)(CH$$_{2}$$COO)_{2}]^{3−}]/[HOC(COO)(CH$$_{2}$$COO)(CH$$_{2}$$COOH)^{2−}$$]

Answer

First Dissociation HOC(COOH)($$CH_{2}$$COOH)_{2}(aq) + $$H_{2}O(l$$) ⇌ $$H_{3}O$$^{+}$$(aq) + HOC(COO)(CH$$_{2}$$COOH)_{2}^{−}(aq) K_{a1} = [H$$_{3}$$O^{+}$$][HOC(COO)($$CH_{2}$$COOH)_{2}^{−}]/[HOC(COOH)($$CH_{2}$$COOH)_{2}]  Second dissociation HOC(COO)($$CH_{2}$$COOH)_{2}^{−}(aq) + $$H_{2}O(l$$) ⇌ $$H_{3}O$$^{+}$$(aq) + [HOC(COO)(CH$$_{2}$$COO)(CH$$_{2}$$COOH)]^{2−}(aq) K_{a2} = [H$$_{3}$$O^{+}$$][HOC(COO)($$CH_{2}$$COO)($$CH_{2}$$COOH)^{2−}$$]/[HOC(COO)(CH$$_{2}$$COOH)_{2}^{−}]  Third dissociation [HOC(COO)(CH$$_{2}$$COO)(CH$$_{2}$$COOH)]^{2−}(aq) + H$$_{2}$$O(l) ⇌ H$$_{3}$$O^{+}(aq$$) + [HOC(COO)($$CH_{2}$$COO)_{2}]^{3−}(aq) K_{a3} = [$$H_{3}O$$^{+}$$][HOC(COO)(CH$$_{2}$$COO)(CH$$_{2}$$COOH)^{2−}$$]/[HOC(COO)($$CH_{2}$$COO)_{2}]^{3−}]

Citric acid (HOC(CO2H)(CH2CO2H)2) is a weak triprotic acid. Write balanced dissociation equations and corresponding equilibrium expressions for each dissociation step.

Citric acid (HOC(CO₂H)(CH₂CO₂H)₂) is a weak triprotic acid. Write balanced dissociation equations and corresponding equilibrium expressions for each dissociation step.