Question

how do we find the fraction of time by using which relation ?​

Answer 1

see the attachment

here 2n is the total moles both n-n moles

Answer 2

by graham's law of diffusion ,

t2/t1 = (M2/M1) ^ 1/2 t2/t1  

mol. mass of H2 = 2

mol. mass of O2= 32

so,

t2/t1= (32/2) ^ 1/2 t2/t1

t2/t1 = (16/1) ^ 1/2 t2/t1  

t2/t1 = 4 t2/ t1

so 1 molecule of oxygen will take same time to escape as 4 molecules of hydrogen

so time taken by some moles of oxygen for 1/2 of hydrogen= 1/2 * 1/4 = 1/8

ans: (1) 1/8