Comparing intracellular to extracellular fluid, the intracellular fluid has a charge relative to the outside of a cell due to the presence of more in that solution.

Comparing intracellular to extracellular fluid, the intracellular fluid has a negative charge relative to the outside of a cell due to the presence of more anions in that solution.

intracellular fluid (ECF)contains more k⁺, Mg²⁺ than outside, hence bears a positive charge due to presence of more cations

extracellular fluid (ICF) contains more  Na⁻,Cl⁻ than inside,hence bears a negative charge due to presence of more anions.

Explanation:

sodium (Na⁻) and potassium (k⁺) plays a vital role in body fluid maintenance also known as body homeostasis and it also plays an important role in any cellular mechanism.  loss of Na⁻-k⁺  balance can leads some fatal conditions.

charged ECF and ICF helps to exchange ions and necessary things quickly during cellular function.