For 109percent labelled oleum if the no. of moles of H2SO4 and free S03 be x and y resp. then whay will be the approx value of x+y/x-y (here / means division)
To find the approximate value of (x + y) / (x - y), where x is the number of moles of H2SO4 and y is the number of moles of free SO3, we need to know the values of x and y.
However, the given information about the "109 percent labelled oleum" is not sufficient to determine the exact values of x and y.
To proceed further, we would require additional information such as the molar mass or the molar ratio between H2SO4 and SO3 in the "109 percent labelled oleum."
Once we have the values for x and y, we can substitute those values into the expression (x + y) / (x - y) to calculate the approximate value.
If I understand the question correctly, H2SO4 is about 98% which makes SO3 about 11%.
So (x+y) = about 109
(x-y) = about 87
(x+y)/(x-y) = about 109/87 = ?