21) In a photochemical reaction the free energy change is:

a) Always negative.
b) Always positive.
c) Always zero.
d) Can be positive or negative.

ANSWER : Can be positive or negative.

22) Quantum yield of photosynthesis is:

a) HCl < HBr
b) HCl > HBr
c) HCl = HBr
d) None of these.

ANSWER : HCl > HBr

23) Activation energy of a chemical reaction can be determined by:

a) Evaluating velocities of reaction at two different temperature.
b) Changing concentrations of reactants.
c) Evaluating rate constants at two different temperatures.
d) Evaluating rate constant at standard temperature.

ANSWER : Evaluating rate constants at two different temperatures.

24) The rate constant is given by K=p.Ze^-E/RT. Which among the following factors should be decreased if we want the reaction to proceed more rapidly?

a) Z
b) E
c) P
d) T

ANSWER : E

25) The reaction H⁺ + OH^- ? H₂O is:

a) Slow
b) Very slow
c) Fast
d) Moderate in speed

ANSWER : Fast

26) For first order reaction, the graph between rate of reaction vs concentration is:

a) Linear
b) Non- linear
c) Curved
d) None of these

ANSWER : Linear

27) In the Arrhenius equation K = A exp (-E/RT), A may be termed as the rate constant at:

a) High temperature.
b) Infinite temperature.
c) Low temperature.
d) Moderate temperature.

ANSWER : Infinite temperature.

28) When retinal absorbs a photon of light it undergoes:

a) Photochemical change
b) Chemical change
c) Isomerisation
d) None of these

ANSWER : Isomerisation

29) Which of the following is incorrect about order of reaction?

a) It can have functional valve.
b) It can assume zero valve.
c) It is based on balanced chemical equation.
d) It is related with actual rate of reaction.

ANSWER : It is based on balanced chemical equation.

30) Method for determination of order of reaction is:

a) Graphical method.
b) Vant Hoff’s differential method.
c) Initial rate method.
d) All of these.

ANSWER : All of these.

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