A definite volume of ammonia gas is passed through a series of electric sparks by which the volume becomes 90 ml . On washing with dilute orthophosphoric acid, the volume is reduced to 84 ml . Which o

Question

A definite volume of ammonia gas is passed through a series of electric sparks by which the volume becomes 90 ml . On washing with dilute orthophosphoric acid, the volume is reduced to 84 ml . Which of the following statement(s) is/are correct regarding the original ammonia sample ?

TestHub · Accepted Answer

Question Explanation: Analyzing the partial decomposition of ammonia.

Concept: Stoichiometry.

Solution: The volume reduction upon washing with acid gives the volume of unreacted ammonia. The remaining volume consists of $N_{2}$ and $H_{2}$ from the decomposition. Using the stoichiometry of decomposition $(N_{2} : H_{2} = 1 : 3)$ , we can find the volumes of $N_{2}$ and $H_{2}$ , which in turn gives the volume of ammonia that decomposed.

Calculation:

Contraction in volume is due to absorption of NH₃ by dilute ortho phosphoric acid.

So remining volume is combined volume of N₂ & H₂ .

$V_{N_{2}} = 3 V_{H_{2}}$ $x + 3 x = 84$ .

$x = 21 m L$

$V_{N_{2}} = 21 m L$

And

V_{H_{2}} = 3 \times 21 = 63 m L

So $V_{N H_{3}}$ To produce 21 mL of N₂, $= 2 \times 21 = 42 m L$

The volume of NH₃ absorbed (unreacted) is

6 m L

.

The initial volume of NH₃ was $42 m L + 6 m L = 48 m L$ .

The percentage decomposition is $\frac{V o l u m eo f N H _{3} d eco m p ose d}{I ni t ia l v o l u m eo f N H _{3}} \times 100 = \frac{42}{48} \times 100 = 87.5%$ .

Final Answer: Statements 2 and 4 are correct.

Chemistry - Eudiometry Question with Solution | TestHub

Options:(select one or more)

Doubts & Discussion