The na+–k+ pump actively transports both sodium and potassium ions across the membrane to compensate for their constant leakage. in which direction is each ion pumped?

Na+ - out from the cell, K+ - into the cell

The mass has escaped into a gas which you can not see so the law stays true.

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