Question

Crystals having fixed number of water molecules are known as

• A. Anhydrous substances
• B. hydrated substances
• C. deliquescent substances
• D. hygroscopic substances

Answer 1

The correct option is B

hydrated substances

The explanation for the right answer:

Option B: hydrated substances

• Hydrated Substance: Word Hydrous is referred to a substance that contains water molecules as a constituent.
• These hydrous compounds are called hydrates.
• For example,$\mathrm{Copper}\mathrm{sulphate}\left({\mathrm{CuSO}}_{4}7{\mathrm{H}}_2\mathrm{O}\right)$.
• Therefore, Option B is the correct answer

The explanations for the wrong answers:

Option A: Anhydrous substances

• Word anhydrous is referred to a substance that does not contain water as a constituent.
• It means the absence of water in a compound. These compounds are called anhydrous compounds or anhydrates.
• For example, anhydrous$\mathrm{Copper}\mathrm{sulphate}$.

• So, option A is the wrong answer.

Option C: Deliquescent substances

• Deliquescent substances are those substances that absorb moisture from the surroundings and get dissolved in the absorbed water and form a solution.
• It does not form crystals

• So, option C is the wrong answer.

Option D: Hygroscopic substances

• Hygroscopic substances are those substances that absorb moisture from the surroundings but do not get dissolved in the absorbed water.
• It does not form solution or crystals

• So, option D is the wrong answer.

Conclusion:

So, Crystals having a fixed number of water molecules are known as hydrated substances

Therefore, Option B is the correct answer.