Which of the following is a strong electrolyte?

Solution

1. Strong electrolytes dissociate completely into ions in solution.
2. ${\text{CH}}_3\text{COOH}$ and ${\text{NH}}_4\text{OH}$ are weak electrolytes.
3. ${\text{H}}_2\text{O}$ is a very weak electrolyte.
4. $\text{NaCl}$ is an ionic salt that dissociates completely as $\text{NaCl}\to {\text{Na}}^{+}+{\text{Cl}}^{-}$.
5. Hence the answer is (B).