Which of the following is a nonelectrolyte? Please state why or why not for each.
a) NaOH
b) HNO3
c) C2H6O (ethanol)
d) KF
e) CH3COOH (acetic acid)
The correct answer and explanation is :
To determine which of the following is a nonelectrolyte, we must understand what an electrolyte is:
An electrolyte is a substance that dissolves in water to produce ions and thus conducts electricity.
A nonelectrolyte is a substance that does not dissociate into ions in solution and therefore does not conduct electricity.
Now, let’s analyze each compound:
a) NaOH (sodium hydroxide)
✅ Electrolyte
- Why? NaOH is a strong base. When dissolved in water, it completely dissociates into Na⁺ and OH⁻ ions: $$
\text{NaOH} \rightarrow \text{Na}^+ + \text{OH}^-
$$ - It produces a solution that conducts electricity well.
b) HNO₃ (nitric acid)
✅ Electrolyte
- Why? HNO₃ is a strong acid, meaning it completely ionizes in water to form H⁺ and NO₃⁻: $$
\text{HNO}_3 \rightarrow \text{H}^+ + \text{NO}_3^-
$$ - Therefore, it is a strong electrolyte and conducts electricity.
c) C₂H₆O (ethanol)
❌ Nonelectrolyte ✅
- Why? Ethanol is an organic compound (an alcohol) that dissolves in water but does not ionize.
- It remains intact as neutral molecules in solution and does not conduct electricity: $$
\text{C}_2\text{H}_6\text{O (ethanol)} \rightarrow \text{No ions produced}
$$ - Thus, ethanol is a nonelectrolyte.
d) KF (potassium fluoride)
✅ Electrolyte
- Why? KF is an ionic compound and a salt. It dissolves in water and completely dissociates into K⁺ and F⁻: $$
\text{KF} \rightarrow \text{K}^+ + \text{F}^-
$$ - Since it produces free-moving ions, it is a strong electrolyte.
e) CH₃COOH (acetic acid)
✅ Electrolyte (but weak)
- Why? Acetic acid is a weak acid, meaning it partially ionizes in water: $$
\text{CH}_3\text{COOH} \rightleftharpoons \text{CH}_3\text{COO}^- + \text{H}^+
$$ - Even though ionization is incomplete, it does conduct electricity, so it’s classified as a weak electrolyte, not a nonelectrolyte.