Question

Chlorine has oxidation number $+7$ in

• A. NaCl
• B. SiCl$_4$
• C. HCl
• D. HClO$_4$
• E. KCl

Hint:

Chemistry Tip: In oxyacids of chlorine, oxidation state rises as number of oxygen atoms increases.

Answer 1

The Correct Option is D

Concept:
Sum of oxidation numbers in a neutral compound is zero. Useful values: - H = $+1$ - O = $-2$ - Alkali metals = $+1$
Step 1: Check simple chlorides.
In NaCl, KCl, HCl: $$Cl=-1$$ In SiCl$_4$: Silicon is $+4$, so each chlorine is: $$Cl=-1$$
Step 2: Find oxidation state in HClO$_4$.
Let oxidation state of Cl = $x$ $$+1 + x + 4(-2)=0$$ $$1+x-8=0$$ $$x=+7$$
Step 3: Final answer.
Thus chlorine has oxidation number $+7$ in HClO$_4$. Therefore option (D). :contentReference[oaicite:1]{index=1}