CBSE Class 12 · 2001 · Delhi · Chemical KineticsShort Answer

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a) Draw a schematic graph showing how the rate of a reaction changes with change in concentration of the reactant.
b) The rate of a reaction is given by: Rate = k[A]

^{2}

[B]

^{1}

. What are the units of the rate and of the rate constant for this reaction?

Solution

(a) For a reaction of positive order, the rate increases with reactant concentration; for a first order reaction, rate

= k [A]

gives a straight line through the origin on a rate-vs-concentration plot (see figure).
(b) Units of rate: mol L

^{- 1}

^{- 1}

.
Overall order

= 2 + 1 = 3

; units of

k

are

(mol L^{- 1})^{1 - 3} s^{- 1}

k : L^{2} mo l^{- 2} s^{- 1}

Structure Rate vs concentration — first order: a straight line through the origin — Rate vs concentration — first order: a straight line through the origin

CBSE Class 12 Board · 2001 · Delhi · Subjective

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