You’re an undergraduate researcher preparing reagents for one of your experiments. You need to make a stock of phosphate-buffered saline (PBS) solution and are following the manufacturer’s instructions, which state that to make 1 L of 10X PBS, you will need to combine 100.0 mM disodium hydrogen phosphate (Na2HPO4), 18 mM potassium dihydrogen phosphate (KH2PO4), 1.37 M sodium chloride (NaCl), and 27 mM potassium chloride (KCl) to an Erlenmeyer flask, before bringing the final volume to 1 L with deionized water.