Oxalic acid is a weak electrolyte because it does not completely dissociate into ions when dissolved in water. Instead, only a small percentage of the oxalic acid molecules dissociate, while the majority remain in their undissociated form. This partial dissociation results in a low concentration of ions in the solution, which is characteristic of weak electrolytes.

Here's a more detailed explanation of why oxalic acid is a weak electrolyte:

1. Intermolecular Hydrogen Bonding: Oxalic acid molecules have two carboxylic acid groups (-COOH) that can form strong hydrogen bonds with each other. These hydrogen bonds hold the molecules together and prevent them from dissociating completely in water.

2. Charge Separation: When oxalic acid does dissociate, it forms oxalate ions (C₂O₄^2-) and hydrogen ions (H⁺). However, the oxalate ions have a negative charge, while the hydrogen ions have a positive charge. These opposite charges attract each other, creating an electrostatic force that pulls the ions back together. This attraction reduces the dissociation of oxalic acid.

3. Solvent Effects: The polarity of the solvent also plays a role in the dissociation of oxalic acid. Water is a polar solvent, meaning it has both positive and negative regions. This polarity can stabilize the ions formed when oxalic acid dissociates, reducing their tendency to recombine. However, in less polar or non-polar solvents, the ions are not stabilized as effectively, leading to a lower degree of dissociation.

In summary, oxalic acid is a weak electrolyte due to intermolecular hydrogen bonding, charge separation, and the polarity of the solvent. These factors prevent complete dissociation of oxalic acid molecules, resulting in a low concentration of ions in solution.