4. Magnesium hydroxide, Mg(OH)2 is another active ingredient of some antacids. How does Mg(OH)2 work to relieve the pain caused by excess stomach acid

Ch4 and ph3 are both covalent since they are composed both of non-metals.    ch4 is non- polar because of  london forces and has a geometry of tetrahedral  ph3 , on the other hand, is umbrella shaped polar and has dipole-dipole intermolecular force (imf) . since ph3 is polar, it has a stronger imf   

Use a magnet to separate iron, evaporate water, i'm not sure how to separate the other two i'm sorry but good luck

Hi + naoh -> h2o + nal