 Good morning to one and all, without today's session we are going to learn about lubricant numericals based on lubricant. So at the end of this session students will be able to explain the acid value and saponification value means what and calculate the acid value and saponification value. So today's content is definition of acid value and saponification value, formula to calculate acid value and saponification value. So introduction lubricant, as we are considering with this lubricant its acid value, saponification value it is very necessary to learn about what you mean by this lubricant. So lubricant is any substance introduced between two moving or sliding surfaces with a view to reduce the frictional resistance between them is known as a lubricant. So what are the main purposes of this lubricant to keep the sliding or moving surfaces apart so that the frictional resistance and consequent destruction of material is minimized. Second, first we are going to learn about acid value or acid number definition the number of milligrams of potassium hydroxide required to neutralize the free acids in one gram of an oil is known as acid value or acid number generally free acids are not present in the lubricants unless refined in faulty manner. Lubricating oil should possess acid value less than 0.1 indicates that oil has been oxidized this will consequently lead to corrosion lubricating oil should possess acid value less than 0.1 indicates that oil has been oxidized this will consequently lead to corrosion besides gum and sludge formation formula acid value of the lubricant can be calculated by the formula that is acid value or acid number is equal to number of m l of n by 10 k o h rundown divided by weight of the oil taken in grams into 5.6 second saponification value definition saponification value is a number of milligrams of a potassium hydroxide required to saponify one gram of oil so saponification value mineral oils do not get saponified but vegetable and animal oils do so consequently this test helps us to ascertain whether the oil under reference is animal or vegetable oil or mineral oil containing minerals and vegetable oil so we can calculate this saponification value by using the formula that is saponification value is equal to volume of n by 2 hc l rundown in blank experiment minus volume of n by 2 hc l rundown in test experiments divided by weight of the oil in grams multiplied by 28 so let us solve some numericals based on acid value first first numerical in an acid value determination experiment 8 grams of oil sample required 4.5 ml of n by 10 k o h solution for neutralization to phenolphthalein end point calculate the acid value of the oil sample molecular weight of the potassium hydroxide is given that is 56 so the formula to be used in this particular case is acid number or value is equal to number of ml of n by 10 k o h rundown divided by weight of the oil taken in grams into 5.6 so the acid value that is by using the formula that is number of ml of n by 10 k o h rundown it is the value for this is 4.5 ml and the weight of oil taken it is 8 grams so by putting this value we can calculate so 4.5 divided by 8 into 5.6 the answer for this question that is acid value is equal to 3.15 second numerical in an acid value determination experiment 9.5 grams of oil sample required 5.7 ml of n by 10 potassium hydroxide solution for neutralization to phenolphthalein end point calculate the acid value of the oil sample again the molecular weight of k o h potassium hydroxide is 56 so here in this case 9.5 grams is a weight of oil which is given which is taken for this experiment and the value for this is 5.7 ml that is number of ml of n by 10 k o h used in this particular case is 5.7 ml so by putting these values in the formula that is acid number or acid value is equal to number of ml of n by 10 k o h rundown divided by weight of the oil taken in grams into 5.6 that is 5.7 divided by 9.5 into 5.6 so the acid value for this oil is a 3.36 so pause the video and answer this question over here the question is dash dash type of oil do not get a saponify options are a vegetable oil b animal oil c mineral oil and d all of this welcome back the answer for this question is c that is mineral oils numerical based on saponification value first numerical 7 gram of an oil sample after saponification with 50 ml of n by 2 alcoholic potassium hydroxide solution and on subsequent titration with n by 2 hcl gave a titration value of 10 ml to phenolphthalein end point a blank experiment was conducted without taking the oil and on repeating the same procedure gave the titre value of 50 ml calculate the saponification value of the oil so here 7 gram of oil is used and the value for titration that is 50 ml for blank titration and 10 ml for back titration that is experimental titration value so saponification value we can calculate by using the formula that is volume of n by 2 hcl rundown in blank experiment that is 50 ml minus volume in ml of the n by 2 hcl rundown in test experiment that is strain ml and weight of the oil in grams that is 7 grams multiplied by 28 so by putting all these values and calculation we are getting the answer that is 50 minus strain divided by 7 into 28 so the saponification value is 160 second numerical 11.5 gram of an oil after saponification with 50 ml of n by 2 alcoholic potassium hydroxide solution and on subsequent titration with n by 2 hcl gave a titration value of 14 ml to phenolphthalein end point a blank experiment was conducted without taking the oil and on repeating the same procedure gave the titre value of 50 ml calculate the saponification value of the oil so here in this case the 11.5 gram of oil is used we are getting 14 ml titration value for the phenolphthalein end point for test experiment and 50 ml for blank so by putting the same values in the formula that is it it is equal to 50 minus 14 divided by 11.5 into 28 that is saponification value is 87.65 so for this particular lecture as a reference I have used a textbook of engineering chemistry by Jane and Jane thank you