Question

The aqueous solution of sugar does not conduct electricity. However, when sodium chloride is added to water, it conducts electricity. How will you explain this statement on the basis of ionization and how it is affected by concentration of sodium chloride?

Answer 1

i) Sugar and $NaCl$ both are soluble in water i.e they both will get dissolved in water.

ii) Sugar just dissolves in water, the reason for sugar to dissolve in water is due to dipole-dipole attractions and hydrogen bonding.

iii) $NaCl$ is soluble in water, where all molecules of $NaCl$ gets ionized/dissociated in water. The molecule of $NaCl$ is ionized to $N{a}^{+}$ and $C{l}^{-}$ ions. Thus, it is an electrolyte.

iv) Sugar, being non-electrolyte does not dissociate into ions and hence cannot conduct electricity while $NaCl$, being electrolyte dissociates into ions $N{a}^{+}$ and $C{l}^{-})$ and can conduct electricity by the movements of free ions in the solution.

$NaCl\to N{a}^{+}+C{l}^{+}$

When concentration of $NaCl$ is increased, more $N{a}^{+}$ and $C{l}^{-}$ ions will be produced, hence conductance increases.