SATHEE: Chemical and Ionic Equilibrium 2 Question 54

Chemical and Ionic Equilibrium 2 Question 54

54. One mole of nitrogen is mixed with three moles of hydrogen in a four litre container. If 0.25 per cent of nitrogen is converted to ammonia by the following reaction

$$ \mathrm{N}{2}(g)+3 \mathrm{H}{2}(g) \rightleftharpoons 2 \mathrm{NH}_{3}(g) \text {, then } $$

calculate the equilibrium constant, $K_{c}$ in concentration units. What will be the value of $K_{c}$ for the following equilibrium?

$$ \frac{1}{2} \mathrm{~N}{2}(g)+\frac{3}{2} \mathrm{H}{2}(g) \rightleftharpoons \mathrm{NH}_{3}(g) $$

$(1981, 4 M)$

Passage Based Questions

Thermal decomposition of gaseous $X_{2}$ to gaseous $X$ at $298 K$ takes place according to the following equation:

$X_{2} (g) ⇌ 2 X (g)$

The standard reaction Gibbs energy, $Δ_{r} G^{\circ}$ , of this reaction is positive. At the start of the reaction, there is one mole of $X_{2}$ and no $X$ . As the reaction proceeds, the number of moles of $X$ formed is given by $β$ . Thus, $β_{equilibrium}$ is the number of moles of $X$ formed at equilibrium. The reaction is carried out at a constant total pressure of 2 bar. Consider the gases to behave ideally.

(Given, $R = 0.083 L bar K^{- 1} {mol}^{- 1}$ )

Show Answer

Solution:

(i) $\mathrm{CH}{3} \mathrm{COOH} \rightleftharpoons \mathrm{CH}{3} \mathrm{COO}^{-}+\mathrm{H}^{+}$

$C (1 - α) C α C α$

If no $HCl$ is present,

$\begin{aligned} [HCl] & = \frac{0.2}{2} = 0.10 M [{CH}_{3} COOH] & = 0.10 M \end{aligned}$

The major contributor of $H^{+}$ in solution is $HCl$ .

$\begin{aligned} K_{a} & = \frac{C α (0.1)}{C (1 - α)} = 1.75 \times 10^{- 5} α & = 1.75 \times 10^{- 4} \end{aligned}$

(ii) $mmol$ of $NaOH$ added $= \frac{6}{40} \times 1000 = 150$

$mmol of HCl = 500 \times 0.2 = 100$

$mmol$ of ${CH}_{3} COOH = 500 \times 0.2 = 100$

After neutralisation, $mmol$ of ${CH}_{3} COOH = 50$

$mmol$ of ${CH}_{3} COONa = 50$

$pH = p K_{a} = 4.75$

Chemical and Ionic Equilibrium 2 Question 54

54. One mole of nitrogen is mixed with three moles of hydrogen in a four litre container. If 0.25 per cent of nitrogen is converted to ammonia by the following reaction

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Chemical and Ionic Equilibrium 2 Question 54

54. One mole of nitrogen is mixed with three moles of hydrogen in a four litre container. If 0.25 per cent of nitrogen is converted to ammonia by the following reaction

Passage Based Questions

Solution:

Engineering Preparation

Medical Preparation

NCERT Books & Solutions

Important Resources

Other Resources

Syllabus

Test Platform

Sample Mock Test

Mentorship

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