Q46 / 150 · MHT CET 2026 (17 April Shift 2) · Chemistry
Which from the following metal chlorides does not contain water of crystallisation ?
- A$\text{LiCl}$
- B$\text{MgCl}_2$
- Correct answerC$\text{CsCl}$
- D$\text{BeCl}_2$
Solution
Alkali metal chlorides generally do not form hydrates, with the exception of lithium chloride, which is deliquescent and crystallises as a dihydrate, $\text{LiCl} \cdot 2\text{H}_2\text{O}$.
Alkaline earth metal chlorides such as $\text{MgCl}_2$ and $\text{BeCl}_2$ readily form hydrates. $\text{MgCl}_2$ crystallises as a hexahydrate, $\text{MgCl}_2 \cdot 6\text{H}_2\text{O}$, and $\text{BeCl}_2$ crystallises as a tetrahydrate, $\text{BeCl}_2 \cdot 4\text{H}_2\text{O}$.
Caesium chloride ($\text{CsCl}$) is an alkali metal chloride that does not form hydrates and crystallises as an anhydrous salt.
Therefore, $\text{CsCl}$ does not contain water of crystallisation.
Answer: $\text{CsCl}$
Alkaline earth metal chlorides such as $\text{MgCl}_2$ and $\text{BeCl}_2$ readily form hydrates. $\text{MgCl}_2$ crystallises as a hexahydrate, $\text{MgCl}_2 \cdot 6\text{H}_2\text{O}$, and $\text{BeCl}_2$ crystallises as a tetrahydrate, $\text{BeCl}_2 \cdot 4\text{H}_2\text{O}$.
Caesium chloride ($\text{CsCl}$) is an alkali metal chloride that does not form hydrates and crystallises as an anhydrous salt.
Therefore, $\text{CsCl}$ does not contain water of crystallisation.
Answer: $\text{CsCl}$
Hence, the correct answer is option: 'C'.