Step 1: Understanding the Concept:
An electrolyte is a substance that produces an electrically conducting solution when dissolved in a polar solvent, such as water. This is because the substance ionizes or dissociates into ions, which are free to move and carry charge. A non-electrolyte is a substance that does not produce ions when dissolved and therefore its solution does not conduct electricity.
Step 2: Key Formula or Approach:
We need to determine which of the given substances is a molecular compound that does not dissociate into ions in water.
- Ionic compounds (salts) are typically strong electrolytes.
- Strong acids and strong bases are strong electrolytes.
- Weak acids and weak bases are weak electrolytes.
- Most covalent/molecular compounds (like sugars, alcohols, urea) are non-electrolytes.
Step 3: Detailed Explanation:
Let's analyze each option:
(A) Urea (CO(NH$_2$)$_2$): Urea is a covalent organic compound. When it dissolves in water, the molecules disperse, but they do not break apart into ions. Therefore, an aqueous solution of urea does not conduct electricity and urea is a non-electrolyte.
(B) Copper Sulphate (CuSO$_4$): This is an ionic salt. In water, it dissociates into copper ions (Cu$^{2+}$) and sulphate ions (SO$_4^{2-}$). These free ions allow the solution to conduct electricity, making it a strong electrolyte.
(C) Silver Nitrate (AgNO$_3$): This is an ionic salt. In water, it dissociates into silver ions (Ag$^{+}$) and nitrate ions (NO$_3^{-}$). It is a strong electrolyte.
(D) Sodium Chloride (NaCl): This is a common ionic salt. In water, it dissociates into sodium ions (Na$^{+}$) and chloride ions (Cl$^{-}$). It is a strong electrolyte.
Step 4: Final Answer:
The aqueous solution of urea does not act as an electrolyte. Therefore, option (A) is correct.