<prompt> The major ion in extracellular compartmentKNaCl-HCO3-  <response>: Ans: b Na Ref: Ganong 22nd ed p. 30, 32Most abundant ion in ECF is Na.ECFMost abundant ion - NaMost abundant cation - NaMost abundant anion - Cl-ICF:-Most abundant cation - KMost abundant anion - PO43- followed by protein.ECF contains more of Na, Cl-, HCO3, Ca2.ICF contains more of K, PO4, organic anion, protein, magnesium. 