 हलो दोस्तो कैसे है आप आज मैं आपको बताने वाला हूँ की वान मोल की वालूँ 6.022 into 10 to the power 23 की होती कोई और नमपर कियो नहीं आपने पडा होगा की मोल is a unit to measure amount of substance अन वान मोल is given by 6.022 into 10 to the power 23 entities वान मोल is given by 6.022 into 10 to the power 23 की है और कोई तुस्तरा नमपर कियो नहीं तो इसको समझने के लिए आपको अज मैं आपको एक देफनीशन बताता हूँ तो मोल की देफनीशन क्या है इसको समचते है देफनीशन अप मोल देफनीशन अप मोल देफनीशन अप मोल is वान मोल is the number of carbon atoms the number of carbon atoms and not any carbon atom but carbon 12 atoms that carbon which has 6 neutrons in its nucleus the number of carbon 12 atoms in exactly 12 gram of carbon the number of carbon 12 atoms in exactly 12 gram of carbon 12 is one mole so i give you 12 gram of carbon that isotope of carbon which has 6 neutrons in its nucleus and i ask you to count them and you will get this number so this is how one mole is defined but then you may ask that a carbon atom is so small how can we count them not count carbon atoms they are so small even if i give you 12 grams and ask you to count you say not possible but in that situation maths will come to our help so let's understand how to count number of carbon 12 atoms in 12 gram of carbon so let's say i give you this maths question that suppose imagine there is a classroom and in this classroom let's say this is a classroom and in this classroom let's say there are n students though we don't know the number of students in the class but let's say that these are different different rows and there are n students in the class 1, 2, 3, 4, 5 and up to n students in the class and i give you this data that let's say all the mass of all the students are same because mass of all the carbon atoms are same carbon 12 atoms so the mass of all the students are same are same that is equal to 50 kg and i also tell you that the total mass of all the students combined is total mass of all students taken in a combined manner is let's say 2000 kg so can you tell me the number of students in the class so that's a very simple maths question you will say here if i know that total mass of all students combined is 2000 kg and total mass of all the students is 50 kg it means 50 kg times the number of students is equal to 2000 kg therefore n will come 2000 by 50 which is 200 by 5 which is 40 isn't it so in a similar way if i i have given you 12 gram of carbon 12 in the previous question and if i so you know in a way total mass of all the carbon 12 atoms so if i tell you the mass of one carbon 12 atom which is 12 u mass of one carbon 12 atom this can be calculated using mass spectroscopy methods mass of one carbon 12 atom is exactly 12 u u is called unified mass and the value of u is 12 into 1.66 times 10 to the power minus 24 grams that's the value of 1 u 1.66 into 10 to the power minus 24 grams so if you know the mass of carbon 12 atom one carbon 12 atom and you know total mass was 12 gram therefore number of carbon 12 atoms in 12 gram of carbon 12 will be equal to total mass of looks like i took total mass of all strands at 2000 kg and here we were taking 2 gram of carbon 12 isn't it so similarly i know the total mass is 2 gram so total mass divided by mass of one carbon 12 atom which is 12 u so it will come g by u and the value of u is 1.66 into 10 to the power minus 24 gram so if you put all these values you'll get the value finally as 6.022 times 10 to the power 23 so dear students therefore for this reason therefore 1 mole is equal to avogadrose number which is 6.022 times 10 to the power 23 so now i think that you know what is the reason behind that why one mole is equal to avogadrose number so hope you understood the concept thank you for your time