If the rate of a chemical reaction becomes slower at a given
temperature, then the
(A) Initial concentration of the reactants remains constant
(B) Free energy of activation is lower
(C) Entropy changes
(D) Free energy of activation is higher

1 Answer

Answer :

(D) Free energy of activation is higher

Related questions

Description : Higher free energy of activation of a chemical reaction (at a given temperature) implies (A) Slower rate of reaction (B) Higher rate of reaction (C) Higher equilibrium conversion (D) Both (B) and (C)

Last Answer : (A) Slower rate of reaction

Description : Rate constant for a first order reaction does not depend upon reaction time, extent of reaction and the initial concentration of reactants; but it is afunction of reaction temperature. In a chemical reaction, the time required to ... Then the order of this reaction is: (A) 0 (B) 1 (C) 2 (D) 3

Last Answer : (B) 1

Description : For a heterogeneous catalytic reaction (A) Free energy of activation is lowered in the presence of catalyst, which remains unchanged at the end of reaction (B) A relatively small amount of catalyst ... with the reactant (D) The surface of the catalyst does not play an important role during reaction

Last Answer : (A) Free energy of activation is lowered in the presence of catalyst, which remains unchanged at the end of reaction

Description : The rate constant of a reaction is a function of the (A) Time of reaction (B) Temperature of the system (C) Extent of reaction (D) Initial concentration of the reactants

Last Answer : (B) Temperature of the system

Description : The rate constant of a reaction depends on the (A) Initial concentration of reactants (B) Time of reaction (C) Temperature of the system (D) Extent of reaction

Last Answer : All of the carbon atoms are sp hybridized

Description : The rate constant of a reaction depends on the (A) Initial concentration of reactants (B) Time of reaction (C) Temperature of the system (D) Extent of reaction

Last Answer : (C) Temperature of the system

Description : What happens when a catalyst is added to a system at equilibrium? A The reaction follows an alternative pathway of lower activation energy. B The heat of reaction decreases. C The potential ... decreases. D The potential energy of the products decreases. E The rate of chemical reaction decreases.

Last Answer : A The reaction follows an alternative pathway of lower activation energy.

Description : Pick out the wrong statement: (A) Chemical reactions with high activation energy are very temperature sensitive (B) A flat velocity profile exists in a plug flow reactor (C) The residence ... D) Half life of a reaction increases with increased initial concentration for reaction orders more than one

Last Answer : (C) The residence time for all the elements of fluid in case of a P.F.R. need not be same

Description : The order of reaction is the number of moles whose concentrations determine the rate of a reaction at a given temperature Give the integrated equation for first order reaction. K = (2.303 / t) * log (a ... a' is the initial concentration of reactants x' is the amount reacted in time t seconds

Last Answer : What is Threshold energy ?

Description : The rate constant of a chemical reaction decreases by decreasing the (A) Pressure (B) Concentration of reactants (C) Temperature (D) Duration of reaction

Last Answer : (C) Temperature

Description : The rate constant of a chemical reaction increases by increasing the (A) Temperature (B) Pressure (C) Reactant's concentration (D) None of these

Last Answer : (A) Temperature

Description : Pick out the wrong statement. (A) Exit age description function (E) and internal age distribution function (I) are related as, E = -(dI/dθ) (B) Chemisorption studies are useful in the ... energy (D) A catalyst increases the potential energy barrier over which the reactants must pass to form products

Last Answer : (D) A catalyst increases the potential energy barrier over which the reactants must pass to form products

Description : Burning of Gasoline initially requires heat before it burns spontaneously. Which of the following does not give a good explanation of this phenomenon?  a. the initial heat rises the enthalpy of the reactant ... of products.  d. The enthalpy of the product is lower than the enthalpy of the reactant

Last Answer : the enthalpy of reactants is lower than the enthalpy of products.

Description : Pick out the wrong statement. (A) In a first order reaction, A → products; the reaction becomes slower as it proceeds, because the concentration of A decreases and the rate is proportional to the concentration ... irreversible reaction, A + B → 2C is k.CA .CB , then the reaction is always elementary

Last Answer : (C) According to the penetration theory, the mass transfer co-efficient decreases, if the exposure time of an eddy to the solute decreases

Description : Pick out the correct statement. (A) A catalyst does not change AH of the reaction (B) A catalyst changes the equilibrium point (C) Law of mass action was suggested by Le-Chatelier (D) The difference between the energy of reactants and that of the products is the activation energy

Last Answer : (A) A catalyst does not change AH of the reaction

Description : For a zero order chemical reaction, the (A) Half life period is directly proportion to the initial concentration of the reactants (B) Plot of products concentration with time is a straight line through the origin (C) Products concentration increases linearly with time (D) All (A), (B) and (C)

Last Answer : (D) All (A), (B) and (C)

Description : What is the order of a chemical reaction in which doubling the initial concentration of the reactants doubles the half life time of the reaction? (A) 0 (B) 1 (C) 2 (D) 3

Last Answer : (A) 0

Description : Pick out the wrong statement. (A) In a multistep reaction, the slowest step is the rate determining step (B) In general, the rate of a reaction becomes triple for every 10°C rise in temperature (C ... energy (D) Molecularity of a reaction cannot be zero but the order of a reaction can be zero

Last Answer : (B) In general, the rate of a reaction becomes triple for every 10°C rise in temperature

Description : In a reversible chemical reaction having two reactants in equilibrium, if the concentration of the reactants are doubled, then the equilibrium constant will (A) Remain the same (B) Be halved (C) Also be doubled (D) Become one fourth

Last Answer : (A) Remain the same

Description : . In a zero order reaction, reactants concentration does not change with time and the (A) Time for half change is half the time taken for completion of the reaction (B) Time for ... is independent of the initial concentration (D) Reaction rate is trebled when the initial concentration is trebled

Last Answer : (A) Time for half change is half the time taken for completion of the reaction

Description : A catalyst (A) Initiates a reaction (B) Lowers the activation energy of reacting molecules (C) Is capable of reacting with any one of the reactants (D) Cannot be recovered chemically unchanged at the end of a chemical reaction

Last Answer : (C) Is capable of reacting with any one of the reactants

Description : Pick out the wrong statement. (A) Use of different catalysts in a reversible catalytic chemical reaction does not change the equilibrium composition (B) Alumina is added as a promoter to ... Arrhenius plot (D) Presence of inerts affects the equilibrium conversion of reactants in a chemical reaction

Last Answer : (C) Activation energy for a reaction is obtained from the intercept of the Arrhenius plot

Description : The excess energy of reactants in a chemical reaction required to dissociate into products is termed as the __________ energy. (A) Activation (B) Potential (C) Binding (D) Threshold

Last Answer : (A) Activation

Description : Pick out the correct statement. (A) In catalytic reactions, the catalyst reacts with the reactants (B) A catalyst initiates a chemical reaction (C) A catalyst lowers the activation energy of ... molecules (D) A catalyst cannot be recovered chemically unchanged at the end of the chemical reaction

Last Answer : (C) A catalyst lowers the activation energy of the reacting molecules

Description : Rate of a chemical reaction is not influenced by the (A) Catalyst (B) Temperature (C) Reactants concentration (D) Number of molecules of reactants taking part in a reaction

Last Answer : (D) Number of molecules of reactants taking part in a reaction

Description : Rate of a chemical reaction is not affected by the (A) Catalyst (B) Temperature (C) Reactant’s concentration (D) Number of molecules of reactants taking part in the reaction

Last Answer : (D) Number of molecules of reactants taking part in the reaction

Description : An increase in which of the following results in a decrease in the rate of the chemical reaction? (a) temperature (b) concentration (c) collision frequency (d) energy of activation

Last Answer : energy of activation

Description : The catalyst in a first order chemical reaction changes the (A) Equilibrium constant (B) Activation energy (C) Heat of formation of the product (D) Heat of reaction

Last Answer : (B) Activation energy

Description : Pick out the wrong statement. (A) Visible radiation provides the necessary activation energy in photochemical reactions (B) The order and molecularity of a complex reaction may not be the same (C) For ... rate constant (k) (D) Molecularity of the reaction is always a whole number greater than zero

Last Answer : (B) The order and molecularity of a complex reaction may not be the same

Description : The rate of a chemical reaction can be affected by: w) temperature x) concentration of products y) concentration of reactants z) all of the above

Last Answer : ANSWER: Z -- ALL OF THE ABOVE

Description : A catalyst is a substance which (a) Changes the equilibrium of a reaction so that the concentration of the product increases (b) Increases the rate of reaction and increases the equilibrium concentration of products (c) Hastens the attainment of equilibrium (d) Increases the activation energy

Last Answer : Ans:(c)

Description : Metabolism is carried out by a large class of proteins that decrease the activation energy required for chemical reactions inside a cell. Therefore they only facilitate reactions that would naturally occur at a much slower rate. What is the name of these proteins that speed up biochemical reactions?

Last Answer : Enzymes

Description : According to the 'law of mass action', the rate of reaction is directlyproportional to the (A) Equilibrium constant (B) Volume of the reaction vessel (C) Nature of the reactants (D) Molar concentration of the reactants

Last Answer : (D) Molar concentration of the reactants

Description : In an exothermic chemical reaction, the reactants compared to the products have (A) Higher temperature (B) More energy (C) Less energy (D) Same energy

Last Answer : (B) More energy

Description : Rate of a chemical reaction is independent of the concentration of the reactants for a __________ reaction. (A) Zero order (B) Third order (C) Consecutive (D) None of these

Last Answer : (A) Zero order

Description : At very high concentration of enzymes, the rate of fermentation chemical reaction is __________ the concentration of reactants. (A) Independent of (B) Directly proportional to (C) Inversely proportional to (D) Proportional to the square of

Last Answer : (A) Independent of

Description : Pick out the wrong statement. (A) Wine, rum & Vodka are prepared by the formulation of fruit juice, sugar beet & rye respectively (B) Protein catalysts are called enzymes (C) The rate ... concentration of reactants at high concentration of enzymes (D) Total sugar content in molasses is about 10%

Last Answer : (D) Total sugar content in molasses is about 10%

Description : The minimum energy required to allow a chemical reaction to proceed is termed as the 'threshold energy '. Chemical reactions with low activation energy are: (A) Always irreversible (B) Insensitive to temperature changes (C) Mostly irreversible (D) Highly temperature sensitive

Last Answer : (B) Insensitive to temperature changes

Description : A system undergoes a change from a given initial state to a given final state either by an irreversible process or by a reversible process, then (where, Δ S1 and Δ SR are the entropy changes of the system for the ... S1is sometimes > Δ SR (C) Δ S1is always > Δ SR (D) Δ S1is always = Δ SR

Last Answer : (C) Δ S1is always > Δ SR

Description : Velocity of a chemical reaction (A) Decreases with increase in temperature (B) Increases with increase of pressure of reactants for all reactions (C) Decreases with increase of reactant concentration (D) None of these

Last Answer : (D) None of these

Description : In a reaction, the threshold energy is equal to (where, A = activation energy N = normal energy of reactants) (A) A (B) N (C) A + N (D) A - N

Last Answer : (C) A + N

Description : Threshold energy in a reaction is equal to the (A) Activation energy (B) Normal energy of reactants (C) Sum of (A) & (B) (D) Neither (A) nor (B)

Last Answer : (C) Sum of (A) & (B)

Description : For a first order chemical reaction, the rate constant (A) Changes on changing the concentration units (B) Is not a function of the unit of time (C) Has unit of time -1 (D) None of these

Last Answer : (C) Has unit of time -1

Description : Enzymes are destroyed, when the (A) Temperature is very high (B) Reactant's concentration is very high (C) Reactant's concentration is very low (D) Reaction rate is independent of the reactant's concentration

Last Answer : (A) Temperature is very high

Description : Pick out the wrong statement. (A) A particular chemical reaction is more temperature sensitive at low temperatures (B) A very high value of equilibrium constant, K (K >> 1) indicates that the ... ) Non-ideal flow takes place in reactors due to recycling, channeling or by creation of stagnant regions

Last Answer : (C) The intercept of the Arrhenius plot is called the 'activation energy

Description : The energy of activation of a chemical reaction: (A) Is same as heat of reaction at constant pressure (B) Is the minimum energy which the molecules must have before the reaction can take place (C) Varies as fifth power of the temperature (D) Both (B) and (C)

Last Answer : (B) Is the minimum energy which the molecules must have before the reaction can take place

Description : Pick out the wrong statement. (A) 'Hold back' is defined as the fraction of material that stays longer than the mean residence time (B) Study of non-ideal flow reactor is done experimentally ... final stages of reaction (D) A batch reactor cannot be used to study the kinetics of catalytic reaction

Last Answer : (D) A batch reactor cannot be used to study the kinetics of catalytic reaction

Description : Pick out the correct statement. (A) A lower temperature favours the reaction of lower activation energy (B) The dispersion number for a reactor/vessel is uL/D (C) The rate controlling step in ... step (D) Pore volume and porosity of a catalyst is measured by Brunauer￾Emmett-Teller (BET) technique

Last Answer : (A) A lower temperature favours the reaction of lower activation energy

Description : The equilibrium constant ‘K’ of a chemical reaction depends on (A) Temperature only (B) Pressure only (C) Temperature and pressure (D) Ratio of reactants

Last Answer : (A) Temperature only