Question

Which of the following does not give ${\mathrm{H}}^{+}$ions in aqueous solution?

• A. $H_2{CO}_3$
• B. $C_2{H}_{5}OH$
• C. ${CH}_{3}COOH$
• D. $H_3{PO}_4$

Answer 1

The correct option is B

${\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OH}$

The explanation for the correct option (B):

• Ethanol (${\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OH}$) in a liquid state is mixed with Water (${\mathrm{H}}_2\mathrm{O}$) to form an aqueous solution of Ethanol. In this reaction, Hydrogen ions (${\mathrm{H}}^{+}$) are not produced in the solution.
• The reaction between Ethanol and Water is:

${\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OH}\left(\mathrm{l}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)\to {\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OH}\left(\mathrm{aq}\right)$

The explanation for the incorrect options:

• (A) When Carbonic acid (${\mathrm{H}}_2{\mathrm{CO}}_3$) is dissolved in Water, it dissociates to produce ${\mathrm{H}}^{+}$ions in an aqueous solution. The reaction between ${\mathrm{H}}_2{\mathrm{CO}}_3$ and ${\mathrm{H}}_2\mathrm{O}$ is:

${\mathrm{H}}_2{\mathrm{CO}}_3\left(\mathrm{aq}\right)\to 2{\mathrm{H}}^{+}\left(\mathrm{aq}\right)+{\mathrm{CO}}_3^{2-}\left(\mathrm{aq}\right)$

• (C) When Acetic acid (${\mathrm{CH}}_3\mathrm{COOH}$) is dissolved in Water, it dissociates to produce ${\mathrm{H}}^{+}$ions in an aqueous solution. The reaction between ${\mathrm{CH}}_3\mathrm{COOH}$ and ${\mathrm{H}}_2\mathrm{O}$ is:

${\mathrm{CH}}_3\mathrm{COOH}\left(\mathrm{aq}\right)\rightleftharpoons {\mathrm{CH}}_3{\mathrm{COO}}^{-}\left(\mathrm{aq}\right)+{\mathrm{H}}^{+}\left(\mathrm{aq}\right)$

• (D) When Phosphoric acid (${\mathrm{H}}_3{\mathrm{PO}}_4$) is dissolved in Water, it dissociates to produce ${\mathrm{H}}^{+}$ions in an aqueous solution. The reaction between ${\mathrm{H}}_3{\mathrm{PO}}_4$ and ${\mathrm{H}}_2\mathrm{O}$ is:

${\mathrm{H}}_3{\mathrm{PO}}_4\left(\mathrm{aq}\right)\to 3{\mathrm{H}}^{+}\left(\mathrm{aq}\right)+{\mathrm{PO}}_4^{3-}\left(\mathrm{aq}\right)$

Final Answer: Hence, option (B) is correct. ${\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OH}$ does not give ${\mathrm{H}}^{+}$ions in an aqueous solution.