00:01
Hello, hi students, let me explain you the question.
00:03
So here, if you lower the freezing point, so here lowering of freezing point, lowering of freezing point, that is for 16 .8 grams of chloroform by 2 .50 degrees centigrade by using chlorine, using chlorine.
00:28
So here gas chlorine chlorine gas how many grams of chlorine gas must be dissolved in must be dissolved in chloroform dissolved in chloroform this is question so first of all i want to tell you what is meant by lowering of freezing point or freezing point depression freezing point depression so the freezing point depression it is nothing but drop in the temperature drop in the temperature at which a substance freezes a substance freezes so when this particular drop in temperature molecular substance freezes so that means it caused whenever a smaller amount of smaller amount of another another non -volatile substance is added another non -volatile substance is added then coming to the solution here so here the substance it is chloro form usually it is freezes a temperature tea but due to the addition of small amount of substance that is chlorine due to the addition of chlorine they drop in temperature so the drop in temperature that is given as drop in temperature that is 2 .5 degrees centigrade okay and here they have given freezing point depression constant so freezing point depression constant depression constant the value depression constant of chloroform it is given as 4 .68 degrees centigrade by m so here we know that so here we have to find out the weight of chlorine gas the molar mass of chlorine gas it is equal to 71 gram per mole so we know delta t f that is freezing point depression is equal to kf into m k f is equal to freezing point depression constant freezing point depression constant and m is equal to molality m is equal to molality so the molality it is nothing but number of moles of solute in a solution corresponding to 1 kg of solvent 1 kg or 1 grams of solvent 1 ,000 grams of solvent so here delta t f what is the delta tf 2 .50 a f 4 .68 into number of moles of solute that is weight by the solute that is molecular weight.
03:55
So here chlorine, weight of chlorine divided by molecular weight of chlorine, molar mass of chlorine into, that means divided by thousand grams of solvent.
04:09
So here they have given in, they have given in, that is 16 .8...