Q78 / 180 · NEET 2026 (Re-NEET) · Chemistry
In potash alum, the ratio of K$^+$ and SO$_4^{2-}$ ions is
- A$3:2$
- Correct answerB$1:2$
- C$2:1$
- D$2:3$
Solution
The chemical formula of potash alum is $\text{K}_2\text{SO}_4 \cdot \text{Al}_2(\text{SO}_4)_3 \cdot 24\text{H}_2\text{O}$.
In one formula unit of potash alum, the number of $\text{K}^+$ ions is $2$.
The number of $\text{SO}_4^{2-}$ ions is $1 + 3 = 4$.
The ratio of $\text{K}^+$ to $\text{SO}_4^{2-}$ ions is $2:4$, which simplifies to $1:2$.
Answer: $1:2$
In one formula unit of potash alum, the number of $\text{K}^+$ ions is $2$.
The number of $\text{SO}_4^{2-}$ ions is $1 + 3 = 4$.
The ratio of $\text{K}^+$ to $\text{SO}_4^{2-}$ ions is $2:4$, which simplifies to $1:2$.
Answer: $1:2$
Hence, the correct answer is option: 'B'.