Description : Arrhenius equation represents graphically the variation between the __________ and temperature. (A) Rate of reaction (B) Frequency factor (C) Rate constant (D) Activation energy
Last Answer : (C) Rate constant
Description : The unit of frequency factor in Arrhenius equation is (A) Same as that of rate constant (B) Same as that of activation energy (C) Dimensionless (D) None of these
Last Answer : (A) Same as that of rate constant
Description : The units of frequency factor in Arrhenius equation (A) Are the same as those of the rate constant (B) Depend on the order of the reaction (C) Depend on temperature, pressure etc. of the reaction (D) Are cycles per unit time
Last Answer : (A) Are the same as those of the rate constant
Description : With increase in temperature, the rate constant obeying Arrhenius equation (A) Increases (B) Decreases (C) Decreases exponentially (D) Can either increase or decrease; depends on the frequency factor
Last Answer : (C) Decreases exponentially
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 : At a given value of E/R (ratio of activation energy and gas constant), the ratio of the rate constants at 500°K and 400°K is 2, if Arrhenius law is used. What will be this ratio, if transition state theory is used with the same value of ‘E/R’? (A) 1.6 (B) 2 (C) 2.24 (D) 2.5
Last Answer : (D) 2.5
Description : According to Arrhenius equation of temperature dependency of rate constant for an elementary reaction (A) k ∝ √T (B) k ∝ e -E/RT (C) k ∝ T e -E/RT (D) None of these
Last Answer : (B) k ∝ e -E/RT
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 reaction rate almost gets doubled for 10°C rise in temperature. This is due to the fact that the (A) Increased temperature reduces the activation energy (B) Fraction of molecules having threshold energy increases (C) Collision frequency increases (D) Value of threshold energy decreases
Last Answer : (B) Fraction of molecules having threshold energy increases
Description : 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
Last Answer : (D) Free energy of activation is higher
Description : Arrhenius equation K = Ae-E a / R T In some reactions, Rate of reaction is directly proportional to. Concentration of catalyst Catalyst used in Bio-Chemical reactions is called. Enzymes Reactions catalyzed by light are called as. Photo catalyzed or Photosensitised reactions
Last Answer : Define order of 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 rate expression for a heterogeneous catalytic reaction is given by, - rA = K.KA PA(1 + KA.PA + KR.PR), where K is surface reaction rate constant and KA and KR are absorption equilibrium constants of A and R respectively. If KR PR ... R and A) (A) E (B) E + ΔHA (C) E + ΔHA - ΔHR ) (D) ΔHA + ΔHR
Last Answer : (C) E + ΔHA - ΔHR )
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 variation of heat of reaction with temperature at constant pressure is given by the __________ law. (A) Kelvin's (B) Antoine’s (C) Kirchoff’s (D) None of these
Last Answer : (C) Kirchoff’s
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 : he quantitative effect of temperature on chemical equilibrium is given by the (A) Van’t-Hoff equation (B) Le-Chatelier's principle (C) Arrhenius equation (D) None of these
Last Answer : (A) Van’t-Hoff equation
Description : Enzymes increases the rate of reactions by (A) Increasing the free energy of activation (B) Decreasing the energy of activation (C) Changing the equilibrium constant of the reaction (D) Increasing the free energy change of the reaction
Last Answer : Answer : B
Description : Enzymes accelerate the rate of reactions by (A) Increasing the equilibrium constant of reactions (B) Increasing the energy of activation (C) Decreasing the energy of activation (D) Decreasing the free energy change of the reaction
Last Answer : Answer : C
Description : Which one of the following statements regarding a catalyst is not correct? A An enzyme is a catalyst that only binds certain substrates. B An enzyme is a protein that is a highly ... increasing the activation energy. D Catalysts do not alter the equilibrium constant for a chemical reaction.
Last Answer : C Catalysts increase the rate of a reaction by altering the mechanism, thereby increasing the activation energy.
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 BrunauerEmmett-Teller (BET) technique
Last Answer : (A) A lower temperature favours the reaction of lower activation energy
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 : Photochemical reaction rate does not depend significantly on temperature, because (A) It is a reversible reaction (B) It is an exothermic reaction (C) The energy of reacting molecules exceeds the activation energy by absorption of light (D) None of these
Last Answer : (C) The energy of reacting molecules exceeds the activation energy by absorption of light
Description : The increase in the rate of reaction with temperature is due to (A) Increase in the number of effective collisions (B) Decrease in activation energy (C) Increase in the average kinetic energy of the reacting molecules (D) None of these
Last Answer : (B) Decrease in activation energy
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 : Variation of equilibrium pressure with temperature for any two phases of a given substances is given by the __________ equation. (A) Gibbs-Duhem (B) Maxwell's (C) Clapeyron (D) None of these
Last Answer : (C) Clapeyron
Description : The reaction step that has its transition state at the highest point on the reaction coordinate is the called the __________. (a) rate-determining step (b) activation energy (c) transition step (d) product favored step
Last Answer : rate-determining step
Description : A catalyst in a chemical reaction (A) Decreases the activation energy (B) Alters the reaction mechanism (C) Increases the frequency of collisions of reacting species (D) All (A), (B) and (C)
Last Answer : (D) All (A), (B) and (C)
Description : The role of a catalyst in a chemical reaction is to change the (A) Equilibrium constant (B) Activation energy (C) Final products (D) Heat of reaction
Last Answer : (B) Activation energy
Description : Catalytic action in a catalytic chemical reaction follows from the ability of catalyst to change the (A) Activation energy (B) Equilibrium constant (C) Heat of reaction (D) None of these
Last Answer : (A) Activation energy
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
Description : The figure given Progress of Reaction Product Substrate B A C D below shows the conversion of a substrate into product by an enzyme. In which one of the four options (A-D ... enzyme enzyme (d) Activation Transition Activation Potential energy state energy energy with without enzyme enzyme
Last Answer : (b) Transition Potential Activation Activation state energy energy energy without with enzyme enzyme
Description : When the wavelength of incident X-rays increases, the angle of diffraction (A) Decreases (B) Increases (C) Remain constant (D) Shows no systematic variation
Last Answer : Option A
Description : When the reaction occurs in the diffusion controlled region, the apparent activation energy as measured is only __________ the true value. (A) Twice (B) Half (C) Equal (D) None of these
Last Answer : (B) Half
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 : A chemical reaction occurs when the energy of the reacting molecules is __________ the activation energy of the reaction. (A) Less than (B) Equal to (C) More than (D) Equal to or more than
Last Answer : (D) Equal to or more than
Description : A chemical reaction occurs, when the energy of the reacting molecules is __________ the activation energy of reaction. (A) Less than (B) Equal to (C) More than (D) Equal to or more than
Description : The reason why a catalyst increases the rate of reaction is that, it (A) Decreases the energy barrier for reaction (B) Increases the activation energy (C) Decreases the molecular collision diameter (D) None of these
Last Answer : (A) Decreases the energy barrier for reaction
Description : Enzymes increase the rates of reactions by (A) Increasing the free energy of activation (B) Decreasing the energy of activation (C) Changing the equilibrium constant of the reaction (D) Increasing the free energy change of the reaction
Description : Pick out the correct statement. (A) Reactions with high activation energies are very temperature sensitive (B) Chemical equilibrium is a static state (C) A photochemical reaction is catalysed by ... occurs when the energy of the reacting molecule is less than the activation energy of the reaction
Last Answer : (A) Reactions with high activation energies are very temperature sensitive (B) Chemical equilibrium is a static state
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 : 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 : Pick out the wrong statement. (A) Catalytic activity of enzyme catalysed reactions which is affected by temperature, pH value & chemical agents, is maximum at a temperature of about 45°C ... in enzyme catalysed reactions can be calculated by using the thermodynamic properties of substrates & prod
Last Answer : (C) Enzymes help in increasing the activation energy of the reaction
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 batch reactor is characterised by (A) Constant residence time (B) Variation in extent of reaction and properties of the reaction mixture with time (C) Variation in reactor volume (D) Very low conversion
Last Answer : (B) Variation in extent of reaction and properties of the reaction mixture with time
Description : The difference between Threshold energy and average energy of the molecules is called activation energy. Ina chemical reaction lowers the rate of reaction the greater will be. The activation energy
Last Answer : How do you define the molecularity of a reaction ?
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 : Which of the following is incorrect about heterogeneous catalysis? a. The most effective catalysts are those which have small surface area b. Seperation of catlyst is easy c. Increase in the rate of reaction is due to decrease in the activation energy d. It is based upon the phenomenon of adsorption
Last Answer : a. The most effective catalysts are those which have small surface area
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 : One of the following is a possible cause of an abrupt frequency variation in a self exited transmitter oscillator circuits resulting to a poor frequency stability to hold a constant frequency ... capacitor in the oscillator D. Loose connections in the oscillator, amplifier, or antenna circuits.
Last Answer : D. Loose connections in the oscillator, amplifier, or antenna circuits.