Animated Solution for Chemistry - s and p-Block Elements: Which of the following statements regarding sulphur is incorrect?

Have you ever wondered what happens to sulphur when you heat it up? It's not just a simple melting process; it's a fascinating journey of molecular transformation! Let's dive into the properties of sulphur and uncover the truth behind these statements.

You might be familiar with the oxygen molecule, $O_2$, and its famous paramagnetic nature. Well, sulphur is right below oxygen in the periodic table, and it shares some family traits!

According to Molecular Orbital Theory, the $S_2$ molecule has unpaired electrons residing in its anti-bonding ${\pi }^{\ast }$ orbitals. These unpaired electrons act like tiny magnets, making the entire molecule paramagnetic. In fact, in the vapor phase, $S_2$ even exhibits a beautiful blue color! So, the statement claiming $S_2$ is paramagnetic is absolutely spot on.

When solid sulphur is heated to around $200^{\circ }\text{C}$, it vaporizes. But what does this vapor look like? At this temperature, the thermal energy is enough to break the intermolecular forces between the solid crystals, but not enough to shatter the robust covalent bonds within the molecules.

As a result, the vapor predominantly consists of puckered $S_8$ rings.

But what if we keep heating it? Imagine pushing the temperature all the way to $600^{\circ }\text{C}$. Now, the thermal energy is intense. The $S_8$ rings can no longer withstand the violent vibrations and begin to break apart. At this high temperature, the gas mainly consists of smaller $S_2$ molecules. So, both statements regarding the behavior of sulphur at $200^{\circ }\text{C}$ and $600^{\circ }\text{C}$ are perfectly correct.

Finally, let's tackle the last statement, which boldly claims that the oxidation state of sulphur is never less than $+4$ in its compounds.

Sulphur, being a versatile Group 16 element, has 6 valence electrons. It can gain 2 electrons to complete its octet, or it can share its electrons with more electronegative elements. This gives it a wide spectrum of possible oxidation states, ranging from $-2$ to $+6$.

Let's look at some classic examples: - In hydrogen sulphide ($H_{2}S$), sulphur is bonded to less electronegative hydrogen atoms, giving it an oxidation state of $-2$. - In its elemental form, the $S_8$ ring, the oxidation state is exactly $0$. - In the thiosulphate ion ($S_2{O}_3^{2-}$), the average oxidation state is $+2$.

Of course, sulphur also forms compounds with higher oxidation states, such as $+4$ in sulphur dioxide ($S{O}_2$) and $+6$ in sulphur trioxide ($S{O}_3$).

The existence of compounds like $H_{2}S$ and the elemental $S_8$ form completely shatters the claim that sulphur's oxidation state is never less than $+4$.

Therefore, the statement asserting this limitation is the incorrect one. And since our mission was to find the incorrect statement, we have our winner!