JEE Chemistry 2024 Question with Solution

Given: The compound is fuming sulfuric acid.

Find: The number of oxygen atoms present in its chemical formula.

Fuming sulfuric acid is also known as oleum. It can be represented as $H_2S_2O_7$, or viewed as $H_2SO_4 + SO_3$.

Counting oxygen atoms:

$$H_2SO_4 \rightarrow 4 \text{ oxygen atoms}$$ $$SO_3 \rightarrow 3 \text{ oxygen atoms}$$

So, total oxygen atoms are

$$4 + 3 = 7$$

We can also verify directly from $H_2S_2O_7$, where the subscript of oxygen is $7$.

Therefore, the number of oxygen atoms in fuming sulfuric acid is $7$. Hence, the correct option is B.

Given: Fuming sulfuric acid is oleum.

Find: The number of oxygen atoms in its formula.

Use the formula of oleum directly:

$$H_2S_2O_7$$

The subscript of oxygen is $7$, so the compound contains $7$ oxygen atoms.

Therefore, the correct option is B.