Calcule a concentração de NaCl (cloreto de sódio) existente em um SF 0,9% 500ml pfv me ajudem não consigo entender de forma alguma​

Phosphorous can form an ion called phosphide, which has the formula p3−. this ion can form an ion called phosphide, which has the formula p3−. this ion properties very similar to those of pforms when a phosphorus atom loses three protonsis called a cationcontains 18 electrons