Question

Ammonia can be dried by

• A. CaO
• B. P$_4$O$_{10}$
• C. Conc. H$_2$SO$_4$
• D. Anhydrous CaCl$_2$

Hint:

Phosphorus pentoxide (P$_4$O$_{10}$) is highly hygroscopic and is commonly used to dry ammonia and other gases.

Answer 1

The Correct Option is B

Step 1: Understand the drying process for ammonia.
Ammonia (NH$_3$) is a gas that can be dried by removing its moisture content. Certain drying agents can be used to absorb the water vapor from ammonia gas.
Step 2: Analyze each option.
- CaO (Calcium oxide) is a desiccant but is generally used for drying gases like carbon dioxide and not ammonia. - P$_4$O$_{10}$ (Phosphorus pentoxide) is a highly effective desiccant that is commonly used to dry ammonia by absorbing moisture and forming phosphoric acid. - Conc. H$_2$SO$_4$ (Concentrated sulfuric acid) is also a drying agent but is more commonly used for drying gases like hydrogen chloride. - Anhydrous CaCl$_2$ (Calcium chloride) is effective in absorbing water but is not as commonly used for drying ammonia specifically.
Step 3: Conclude the correct answer.
Phosphorus pentoxide (P$_4$O$_{10}$) is the most effective and common drying agent for ammonia.
Final Answer: \[ \boxed{\text{P}_4\text{O}_{10}} \]