Description : $ Coenzymes are usually proteins ! The term feedback refers to the effect of enzyme concentration on its rate of reaction.
Last Answer : $ Coenzymes are usually proteins ! The term feedback refers to the effect of enzyme concentration on its rate ... wrong D. If both As and R are wrong.
Description : Feedback term refers to (A) Effect of substrate on rate of enzymatic reaction (B) Effect of end product on rate reaction (C) Effect of enzyme concentration on rate of reaction (D) Effect of external compound on rate of reaction
Last Answer : Answer : B
Description : Which of the following factors has no effect on the rate of SN1 reactions? (a) the nature of the alkyl halide (b) the nature of the leaving group (c) the concentration of the alkyl halide (d) the concentration of the nucleophile
Last Answer : the concentration of the nucleophile
Description : Which of the following statements concerning SN2 reactions of alkyl halides is not correct? (a) The rate of reaction depends on the concentration of the nucleophile. (b) The rate of reaction depends on the ... carbon of the C-Br bond. (d) All alkyl iodides react more rapidly than all alkyl chlorides
Last Answer : All alkyl iodides react more rapidly than all alkyl chlorides
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 : 25. In a reaction, A + B Product, rate is doubled when the concentration of B is doubled, and rate increases by a factor of 8 when the concentrations of both the reactants (A and B) are doubled, rate law for the reaction can be ... Rate = k[A] [B]2 (3) Rate = k[A]2 [B]2 (4) Rate = k[A] [B]
Last Answer : Rate = k[A]2 [B] (
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 : What effect would a low carbon dioxide concentration have on the rate of photosynthesis?
Last Answer : What is the answer ?
Description : The antibacterial action of aminoglycoside antibiotics is characterized by: A. Concentration dependent rate of bacterial cell killing B. Concentration dependent prolonged postantibiotic effect C. More pronounced bactericidal effect in anaerobic medium D. Both 'A' and 'B' are correct
Last Answer : D. Both 'A' and 'B' are correct
Description : What affect does the concentration of reactants have on the rate of a reaction?
Last Answer : Need answer
Description : The rate of an enzyme catalyzed reaction was measured using several substrate concentrations that were much lower than Km, the dependence of reaction velocity on substrate concentration can best be ... constant fraction of Vmax (C) Equal to Km (D) Proportional to the substrate concentration
Last Answer : Answer : C
Description : The Michaehis-Menten hypothesis: (A) Postulates the formation of an enzyme substrate complex (B) Enables us to calculate the isoelectric point of an enzyme (C) States that the ... independent of substrate concentration (D) States that the reaction rate is proportional to substrate concentration
Last Answer : Answer : A
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 : 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 : Rate of reaction can be expressed as –dc/dt where dc is small decreasing concentration in time dt seconds, (-) sign indicates that the concentration decreases with time. For every 10 degrees rise of temperature, the rate of reaction is generally. Doubled
Last Answer : Which equation gives the relation between specific rate (k) and Temperature ?
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 : Sum of the powers of the concentration terms in the rate equation is called the __________ of the reaction. (A) Order (B) Overall order (C) Molecularity (D) None of these
Last Answer : (B) Overall order
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 : The rate constant of a first order reaction depends on the (A) Concentration of the reactant (B) Temperature (C) Concentration of the product (D) Time
Last Answer : (B) Temperature
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 : For the chemical reaction X → Y, it is observed that, on doubling the concentration of 'X', the reaction rate quadruples. If the reaction rate is proportional to Cx n , then what is the value of ‘n’? (A) 1/4 (B) 2 (C) 4 (D) 16
Last Answer : (C) 4
Description : The knowledge of initial concentration and rate constant is necessary to determine the half life time of a reaction of __________ order. A) Zero (B) First (C) Second (D) None of these
Last Answer : (C) Second
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 : For the chemical reaction P → Q, it is found that the rate of reaction doubles as the concentration of 'P' is doubled. If the reaction rate is proportional to Cp n , then what is the value of 'n' for this chemical reaction? (A) 0 (B) 1 (C) 2 (D) 3
Description : Second order consecutive irreversible reaction as shown in the bellow figure, were carried out in a constant volume isothermal batch reactor with different initial feed compositions. Reactor temperature was same in all the cases. In experiments ... constants (k1 /k2 )? (A) 1/4 (B) 1/2 (C) 2 (D) 4
Last Answer : (A) 1/4
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 : The reaction A → B is conducted in an adiabatic plug flow reactor (PFR). Pure A at a concentration of 2 kmol/m3 is fed to the reactor at the rate of 0.01 m3 /s and at a temperature of 500 K. If the exit ... /kmole. K (may be assumed to be independent of temperature)) (A) 400 (B) 500 (C) 600 (D) 1000
Last Answer : (C) 600
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 a chemical reaction as shown in the bellow figure, it is observed that the (i) Rate of formation of 'P' is doubled on doubling the concentration of 'X' (ii) Rate of formation of 'P' is quadrupled ... of the above chemical reaction? (A) Zeroth order (B) First order (C) Second order (D) Third order
Last Answer : (D) Third order
Description : What is the order of chemical reaction as shown in the bellow figure, if it is found that the reaction rate doubles on doubling the concentration of B and also the reaction rate doubles when the concentrations of both A & B ... the concentrations of both B & C were doubled? (A) 1 (B) 2 (C) 3 (D) 4
Last Answer : (B) 2
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 : Which of the following does not produce a change in the value of rate constant of a reaction? (A) Pressure (B) Temperature (C) Concentration and catalyst (D) None of these
Last Answer : (C) Concentration and catalyst
Description : With the same reaction time, initial concentration and feed rate, the reaction 2A → B is carried out separately in CSTR and P.F. reactor of equal volumes. The conversion will be (A) Higher in P.F. reactor (B) Higher in CSTR (C) Same in both the reactors (D) Data insufficient; can't be predicted
Last Answer : (A) Higher in P.F. reactor
Description : Overall rate of reaction in a heterogeneous catalytic reaction depends upon the mass and energy transfer from the fluid to solid surface and its rate of reaction is usually __________ the concentration of ... to (B) Independent of (C) Inversely proportional to (D) Proportional to the square o
Last Answer : (A) Proportional to
Description : Pick out the correct statement. (A) A chemical reaction accompanied by absorption of heat is called an exothermic reaction (B) A chemical reaction accompanied by evolution of heat is called an ... does not change on changing the concentration units (D) Chemical equilibrium state is dynamic in nature
Last Answer : (C) The rate constant for a first order reaction does not change on changing the concentration units
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 : 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 : In a CSTR __________ varies with time. (A) Reaction rate (B) Concentration (C) Both (A) & (B) (D) Neither (A) nor (B)
Last Answer : (D) Neither (A) nor (B)
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
Last Answer : (C) Temperature of the system
Description : What is the order of a chemical reaction whose rate is deter-mined by the variation of one concentration term only? (A) Zero (B) First (C) Second (D) Third
Last Answer : (B) First
Description : What is the value of 'n' if the reaction rate of the chemical reaction A → B, is proportional to CA n and it is found that the reaction rate triples, when the concentration of 'A' is increased 9 times? (A) 1/2 (B) 1/3 (C) 1/9 (D) 3
Last Answer : (A) 1/2
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 : In a chemical reaction, represented by as shown in the bellow figure, it is observed that the (i) Rate of reaction increases by a factor of 4 on doubling the concentration of the reactant. (ii) Rate of reaction increases ... where, CA = concentration of the reactant) (A) CA (B) CA 2 (C) CA 3 (D) CA
Last Answer : (B) CA 2
Description : The rate of the chemical reaction A → B doubles as the concentration of A i.e.., CA is doubled. If rate of reaction is proportional to CA n , then what is the value of n for this reaction? (A) 0 (B) 0.5 (C) 1 (D) 2
Last Answer : (C) 1
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 : A second order liquid phase reaction, A → B, is carried out in a mixed flow reactor operated in semi batch mode (no exit stream). The reactant A at concentration CAF is fed to the reactor at a volumetric flow rate of F. The volume ... 2V (C) d(VCA )/dt = -FCA - kCA 2V (D) d(VCA )/dt = FCAF - kCA 2V
Last Answer : (D) d(VCA )/dt = FCAF - kCA 2V
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 : . 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