40% of HI undergoes decomposition to H2 and I2 at 300 K. ΔG° for this decomposition reaction at one atmosphere pressure is _____ J mol–1. [nearest integer]
(Use R = 8.31 J K–1 mol–1; log 2 = 0.3010, ln 10 = 2.3, log 3 = 0.477)
(Use R = 8.31 J K–1 mol–1; log 2 = 0.3010, ln 10 = 2.3, log 3 = 0.477)
Correct Answer: 2735
Solution and Explanation
\(HI ⇄ \frac{1}{2} H_2 + \frac{1}{2} l_2\)
\(1\) \(0\) \(0\)
\(1 - α\) \(α / 2\) \(α / 2\)
\(ΔG° = - RTInΚ\)
\(= - RTIn \frac{( ( \frac{α}{2} )^{1 / 2} ( \frac{α}{2})^{1 / 2} ) }{1 - α }\)
\(= RTIn \frac{α}{2(1 - α )}\)
( \(α\) = 0.4 )
\(= - 8.314 × 300In \frac{0.4}{2 × 0.6 }\)
\(= + 8.314 × 300 In3\)
\(= 2735 J / mol\)
Top Questions on Order of Reaction
The cycloalkene (X) on bromination consumes one mole of bromine per mole of (X) and gives the product (Y) in which C : Br ratio is \(3:1\). The percentage of bromine in the product (Y) is _________ % (Nearest integer).
Given:
\[ \text{H} = 1,\quad \text{C} = 12,\quad \text{O} = 16,\quad \text{Br} = 80 \]- JEE Main - 2026
- Chemistry
- Order of Reaction
- A reaction is of second order with respect to a reactant. How is the rate of reaction affected if the concentration of the reactant is (i) doubled, (ii) reduced to half?
- CBSE CLASS XII - 2025
- Chemistry
- Order of Reaction
- For a first-order reaction, the ratio of time required is $ \frac{t_1}{t_2} $, if $ t_1 $ is the time consumed when reactant reaches $ \frac{1}{4} $ of initial concentration and $ t_2 $ is the time when it reaches $ \frac{1}{8} $ of initial concentration.
- JEE Main - 2025
- Chemistry
- Order of Reaction
- For a first-order reaction, the slope of the graph between \(\log[A]\) vs time is equal to:
- MHT CET - 2025
- Chemistry
- Order of Reaction
- Which of the following plots gives a straight line for a zero-order reaction?
- MHT CET - 2025
- Chemistry
- Order of Reaction
Questions Asked in JEE Main exam
- Two point charges of \(1\,\text{nC}\) and \(2\,\text{nC}\) are placed at two corners of an equilateral triangle of side \(3\) cm. The work done in bringing a charge of \(3\,\text{nC}\) from infinity to the third corner of the triangle is ________ \(\mu\text{J}\). \[ \left(\frac{1}{4\pi\varepsilon_0}=9\times10^9\,\text{N m}^2\text{C}^{-2}\right) \]
- JEE Main - 2026
- Electrostatics
- Evaluate: \[ \frac{6}{3^{26}}+\frac{10\cdot1}{3^{25}}+\frac{10\cdot2}{3^{24}}+\frac{10\cdot2^{2}}{3^{23}}+\cdots+\frac{10\cdot2^{24}}{3}. \]
- JEE Main - 2026
- Integral Calculus
In the given figure, the blocks $A$, $B$ and $C$ weigh $4\,\text{kg}$, $6\,\text{kg}$ and $8\,\text{kg}$ respectively. The coefficient of sliding friction between any two surfaces is $0.5$. The force $\vec{F}$ required to slide the block $C$ with constant speed is ___ N.
(Given: $g = 10\,\text{m s}^{-2}$)
- JEE Main - 2026
- Rotational Mechanics
- If the coefficient of \( x \) in the expansion of \[ (ax^2 + bx + c)(1 - 2x)^{26} \] is \(-56\) and the coefficients of \( x^2 \) and \( x^3 \) are both zero, then \( a + b + c \) is equal to
- JEE Main - 2026
- Binomial theorem
The equivalent resistance between the points \(A\) and \(B\) in the given circuit is \[ \frac{x}{5}\,\Omega. \] Find the value of \(x\).
- JEE Main - 2026
- Current electricity
Concepts Used:
Order of Reaction
The Order of reaction refers to the relationship between the rate of a chemical reaction and the concentration of the species taking part in it. In order to obtain the reaction order, the rate equation of the reaction will given in the question.
Characteristics of the reaction order
- Reaction order represents the number of species whose concentration directly affects the rate of reaction.
- It can be obtained by adding all the exponents of the concentration terms in the rate expression.
- The order of reaction does not depend on the stoichiometric coefficients corresponding to each species in the balanced reaction.
- The reaction order of a chemical reaction is always defined with the help of reactant concentrations and not with product concentrations.
- Integer or a fraction form the value of the order of reaction will be there and it can be zero.