Write four differences between rate of reaction and rate constant.

Rate of reaction Rate constant It depends upon the concentration of the reactant It is independent of the concentration of the reactant, but it depends upon temperature It is expressed in terms of consumption of reactants or formation of products per unit time It is proportionality constant in differential form of rate law. Rate of reaction Rate constant It generally decreases with the progress of the reaction It does not depend on the progress of the reaction Unit is mol L - 1 sec - 1 It changes according to order of the reaction.

Write four differences between molecularity and order of a reaction.

Molecularity of a reaction Order of a reaction It is equal to the sum of the stoichiometric coefficients of the reactants of the elementary reaction. It is equal to the sum of the powers of concentration terms in the rate law equation. Molecularity of a reaction Order of a reaction Molecularity is calculated from the balanced chemical equation Order of a reaction is determined experimentally Molecularity of a reaction Order of a reaction Molecularity is always a whole number as 1 , 2 , 3 and never a fraction Order of a reaction may be 0 , 1 , 2 , 3 or fractions Molecularity of a reaction Order of a reaction The elementary reaction may be unimolecular, bimolecular or termolecular The reaction may be zero order, first order, second order or third order.

Prove that half life period of a first order reaction does not depend on the initial concentration of the reactants.

From the integrated rate equation for a first order reaction, k = 2 . 303 t log A ∘ A At t 1 2 , A = A ∘ 2 . Substituting in the above equation, k = 2 . 303 t 1 2 log A ∘ A ∘ 2 k = 2 . 303 t 1 2 log 2 t 1 2 = 2 . 303 k × 0 . 301 t 1 2 = 0 . 693 k This proves that the half life period of a first order reaction doesn't depend upon the initial concentration of the reactants.

Find the order of reaction and the unit of rate constant for the following reaction by their rate expression: C 2 H 5 Cl g → C 2 H 4 + HCl g ; velocity = k C 2 H 5 Cl

The order of reaction can be defined as the power dependence of rate on the concentration of all reactants. Given rate of reaction is k C 2 H 5 Cl . Therefore, order of the reaction is 1 . Units of rate constant are mol L - 1 s - 1 mol L - 1 = s - 1

Find the order of reaction and the unit of rate constant for the following reaction by their rate expression: CH 3 CHO g → CH 4 g + CO g ; velocity = k CH 3 CHO 3 2

The order of reaction can be defined as the power dependence of rate on the concentration of all reactants. Given rate of reaction is k CH 3 CHO 3 2 . Therefore, order of the reaction is 3 2 . Units of rate constant are mol L - 1 s - 1 mol 3 2 L 3 2 = L 1 2 mol 1 2 s - 1

Find the order of reaction and the unit of rate constant for the following reaction by their rate expression: H 2 O 2 aq + 3 I - aq + 2 H + → 2 H 2 O l ; velocity = k H 2 O 2 I -

The order of reaction can be defined as the power dependence of rate on the concentration of all reactants. Given rate of reaction is k H 2 O 2 I - . Therefore, order of the reaction is 2 . Units of rate constant are mol L - 1 s - 1 mol L - 1 2 = L mol - 1 s - 1

Find the order of reaction and the unit of rate constant for the following reaction by their rate expression: 3 NO g → N 2 O g ; velocity = k NO 2

The order of reaction can be defined as the power dependence of rate on the concentration of all reactants. Given rate of reaction is k NO 2 . Therefore, order of the reaction is 2 . Units of rate constant are mol L - 1 s - 1 mol L - 1 2 = L mol - 1 s - 1

Derive an expression for rate constant of first order reaction.

A first order reaction is that, in which the concentration of only one reactant changes or in which the rate of reaction is proportional to the first power of the concentration of the reactant. In general, such a reaction is represented as, A → Product At t = 0 a 0 At t = t a - x x The initial concentration of A is a mole L - 1 and its concentration after time t is ( a – x ) mole L - 1 . This means during the time interval t , x mole L – 1 of A has reacted. The rate of reaction at any time t is given by the following first order kinetics. dx dt = k a - x where k is the rate constant of the reaction. dx a - x = kdt This is differential rate equation and can be solved by integration. ∫ dx a - x = k ∫ dt - ln a - x = k . t + C . . . . . ( 1 ) where C is integration constant. The constant C can be evaluated by applying the initial condition of the reaction i.e. when t = 0 , x = 0 . Putting these in equation (1), we get C = – ln a Putting the value of C in equation (1), we get – ln ( a – x ) = k . t – lna k = 1 t ln a a - x = 2 . 303 t log a a - x . . . . . ( 2 ) Equation (2) is expression of rate constant for a first order reaction.

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EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR CHEMISTRY>Chapter -1 - Chemical Kinetics>Madhya Pradesh Board-2019>Q 4

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Write the Arrhenius equation.

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