In the reaction mgcl2 + 2koh mg(oh)2 + 2kcl, if 3 moles mgcl2 are added to 4 moles koh what determines how much mg(oh)2 is made

Every mole of MgCl2 reacts with 2 moles of KOH, therefore the 4 moles of KOH will only react with 2 moles of MgCl2, making it the limiting reagent and therefore KOH determines how much Mg(OH)2 is produced.

Ch4 is nonpolar and insoluble in water. since all of the hydrogen atoms are evenly spread around the carbon atom even through the c h bond is polar all the poles cancel each other out.