The number of oxygen atoms present in chemical formula of fuming sulphuric acid is _______.
To determine the number of oxygen atoms in fuming sulfuric acid, first recognize its chemical formula. Fuming sulfuric acid is also known as oleum and is a combination of sulfuric acid (H2SO4) and sulfur trioxide (SO3). A common representation is H2S2O7, which can be viewed as H2SO4 + SO3.
Counting the oxygen atoms, H2SO4 contains 4 oxygen atoms and SO3 contains 3 oxygen atoms, summing up as:
Total = 7 oxygen atoms.
We verify that the result, 7, falls within the provided range [7,7]. Thus, the number of oxygen atoms in fuming sulphuric acid is 7.
Fuming sulphuric acid is also known as oleum. It is formed by dissolving sulfur trioxide (SO3) in concentrated sulfuric acid (H2SO4). The general formula for oleum can be represented as H2S2O7.
In the chemical formula H2S2O7, let's count the oxygen atoms:
Therefore, the number of oxygen atoms in fuming sulphuric acid (oleum) is 7.
This value falls within the specified range of 7 to 7, confirming the correctness of our calculation.
Method used for separation of mixture of products (B and C) obtained in the following reaction is: 
A substance 'X' (1.5 g) dissolved in 150 g of a solvent 'Y' (molar mass = 300 g mol$^{-1}$) led to an elevation of the boiling point by 0.5 K. The relative lowering in the vapour pressure of the solvent 'Y' is $____________ \(\times 10^{-2}\). (nearest integer)
[Given : $K_{b}$ of the solvent = 5.0 K kg mol$^{-1}$]
Assume the solution to be dilute and no association or dissociation of X takes place in solution.