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Chemical Kinetics

Long Answer Type

241. Ammonia and oxygen react at high temperatures according to the equation
4NH₃(g) + 5O₂(g) 4NO(g) → + 6H₂O(g)
In an experiment, the rate of formation of NO was found to be 3.2 x 10^–3 mol L^–1 S^–1. Calculate the rate of disappearance of ammonia and the rate of formation of water.

587 Views

Short Answer Type

242. The decomposition of N₂O₅ in CCl₄ at 318 K has been studied by monitoring the concentration of N₂O₅ in the solution. Initially the concentration of N₂O₅ is 2.33 M and after 184 minutes, it is reduced to 2.08 M. The reaction takes place according to the equation:

2 N_{2} O_{5} (g) \to 4 {NO}_{2} (g) + O_{2} (g)

Calculate the average rate of this reaction in terms of hours, minutes and seconds. What is the rate of production of NO₂ during this period?

1240 Views

243. For a reaction 2I^– + 2H⁺ → I₂ (s) + H₂(g), if the initial concentration of I^–1 was 0.80 mol L^–1 and concentration after 20 minutes was 0.68 mol L^–1. Calculate the rate of disappearance of I^– and rate of appearance of I₂.

Rate = - \frac{1}{2} \frac{∆ {[I]}^{-}}{∆ t} = - \frac{1}{2} \frac{∆ [H^{+}]}{∆ t} = \frac{∆ [I_{2}]}{∆ t} = \frac{∆ [H_{2}]}{∆ t}

We have to calculate the rate of disappearance I^–1 and rate of appearance of I₂, hence

Rate = - \frac{1}{2} \frac{∆ {[I]}^{-}}{∆ t} = \frac{∆ [I_{2}]}{∆ t}

but

\frac{∆ {[I]}^{-}}{∆ t} = \frac{Change in concentration of I^{-}}{Change in time} = \frac{(0.68 - 0.80) mol L^{- 1}}{(20 - 0) minutes} = \frac{0.12}{20} = 0.006 mol L^{- 1} \min^{- 1}

We know that

\frac{∆ [I_{2}]}{∆ t} = \frac{1}{2} \frac{∆ {[I]}^{-}}{∆ t} = \frac{1}{2} \times 0.006 mol L^{- 1} \min^{- 1}

= 0.003 mol L^{- 1} \min^{- 1} .

127 Views

Long Answer Type

244. The rate of change in concentration of C in the reaction 2A + B → 2C + 3D was reported 1.0 M sec^–1. Calculate the reaction rate as well as rate of change of concentration of A, B and D.

165 Views

Short Answer Type

245. For the reaction: 3H₂(g) + N₂ (g) → 2NH₃(g) express the rate of reaction in terms of

- \frac{d [H_{2}]}{dt}, \frac{- d [N_{2}]}{dt} and \frac{d [{NH}_{3}]}{dt} .

119 Views

246. How is the rate of formation of NO₂ related to the rate of disappearance of NO and O₂ in the reaction given below:

2 NO (g) + O_{2} (g) \to 2 {NO}_{2} (g)

114 Views

247. How is the rate of formation of Br₂ is related to the rate of disappearance of Br, BrO₃^– and H⁺ in the reaction given below:

5 Br - (aq) + {BrO}_{3}^{-} (aq) + 6 H^{+} (aq) \to 3 {Br}_{2} (aq) + 3 H_{2} O (l)

123 Views

248. The gas phase decomposition of acetaldehyde
CH₃CHO(g) → CH₄(g) + CO(g)
at 680 K is observed to follow the rate expression

rate = \frac{- d [{CH}_{3} CHO]}{dt} = k {[{CH}_{3} CHO]}^{1 / 2}

If the rate of the decomposition is followed by monitoring the partial pressure of the acetaldehyde, we can express the rate as

\frac{{dp}_{{CH}_{3} CHO}}{dt} = k {[p_{{CH}_{3} CHO}]}^{3 / 2}

If the pressure is measured in atmosphere and time in minutes then
(i) What are the units of the rate of reaction?
(ii) What are the units of rate constant k?

108 Views

249. State the order with respect to each reactant and overall order for the reaction
2H₂(g) + 2NO(g) → 2H₂O(g) + N₂(g)
Rate = k[H₂][NO]²

155 Views

250. For a reaction: A + B → Products
The rate law expression is, rate = k[A]^1/3.[B]². What is the order of reaction?

128 Views

Previous Year Papers

Test Series

Test Yourself

Long Answer Type

Short Answer Type

243. For a reaction 2I– + 2H+ → I2 (s) + H2(g), if the initial concentration of I–1 was 0.80 mol L–1 and concentration after 20 minutes was 0.68 mol L–1. Calculate the rate of disappearance of I– and rate of appearance of I2.

Long Answer Type

Short Answer Type

243. For a reaction 2I^– + 2H⁺ → I₂ (s) + H₂(g), if the initial concentration of I^–1 was 0.80 mol L^–1 and concentration after 20 minutes was 0.68 mol L^–1. Calculate the rate of disappearance of I^– and rate of appearance of I₂.