The reactions with low activation energy are _____________________?

Related Mcqs:

1. 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 >> (1 + KA PA), the apparent activation energy EA is equal to (given E is the activation energy for the reaction and ΔHR and ΔHA are the activation energies of adsorption of R and A) ?

   A. E
   B. E + ΔHA
   C. E + ΔHA – ΔHR)
   D. ΔHA + ΔHR

2. 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

3. Reactions with high activation energy are_____________________?

   A. Very temperature sensitive
   B. Temperature insensitive
   C. Always irreversible
   D. Always reversible

4. 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

5. 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

6. 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

7. 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.

8. 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.

9. If the pore diffusion controls in a catalytic reaction, the apparent activation energy Ea is equal to___________________?

   A. The intrinsic activation energy E
   B. (E + ED) where ED is activation due to diffusion
   C. (E + ED)/2
   D. ED/2

10. Enzymes (a protein) are catalysts found in organisms. Its efficiency of catalysing a reaction is due to its capacity to lower the activation energy of the reaction. The enzyme ptyalin used for food digestion is present in ___________________?

    A. Blood
    B. Saliva
    C. Intestine
    D. Gland