Question

The number of moles of ammonia present in 5.6 dm\(^3\) of its volume at S.T.P. is?

• A. 0.75
• B. 1.0
• C. 0.50
• D. 0.25

Hint:

At S.T.P., 1 mole of gas occupies 22.4 dm\(^3\). Use this relationship to calculate the number of moles for any gas.

Answer 1

The Correct Option is D

Step 1: Understanding the question.
At standard temperature and pressure (S.T.P.), 1 mole of any gas occupies 22.4 dm\(^3\) of volume. We are given the volume of ammonia as 5.6 dm\(^3\). To calculate the number of moles, we can use the relationship:
\[ \text{Number of moles} = \frac{\text{Volume of gas}}{\text{Molar volume at S.T.P.}} \] Step 2: Calculating the moles.
Using the formula, we get: \[ \text{Number of moles} = \frac{5.6 \, \text{dm}^3}{22.4 \, \text{dm}^3/\text{mol}} = 0.25 \, \text{moles} \] Step 3: Conclusion.
The number of moles of ammonia in 5.6 dm\(^3\) at S.T.P. is 0.25 moles, so the correct answer is (D).