Chemical Kinetics

This is a Short Answer Type Question as classified in NCERT Exemplar

The concentration of the reactants does not change with time in a zero- order reaction, and the rate of concentration remains constant.

R= [R]₀ – Kt

Kt = [R]₀

t = $\frac{\left. [\mathrm{R}\right]{}_0}{\mathrm{K}}$

 

This is a Short Answer Type Question as classified in NCERT Exemplar

The concentration of the reactants does not change with time in a zero- order reaction, and the rate of concentration remains constant.

This is a Short Answer Type Question as classified in NCERT Exemplar

Let order of reaction be = n

rate = k [A]ⁿ- (i)

27r = k [3A]ⁿ- (ii)

Divide (ii) by (i)

$\frac{27\mathbf{r}}{\mathbf{r}}$  =  $\frac{27\mathbf{r}}{\mathbf{r}}$   k [3A]nn

3ⁿ = 27

n = 3

This is a Short Answer Type Question as classified in NCERT Exemplar

The order and molecularity of elementary reactions are the same. As a result of a single collision between two molecules or ions, a complicated process occurs. A reaction mechanism is a set of elementary reactions.

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Experimentally, the reaction's rate law can be calculated.

Step 1

2NO (g) + O₂ (g)→2NO₂ (g)

O₂ (g) is taken in excess

x molecules of NO number reacting with excess of O₂

r = k [NO]^x

Step 2

2NO (g) + O₂ (g)→2NO₂ (g)

When 2No (g)is taken in excess

Y molecules of O₂ reacting with excess of [NO]

rate = k [O₂]^y

rate = k [NO]^x [NO]^y

This is a Short Answer Type Question as classified in NCERT Exemplar

Given: Order of the reaction = 0

We know that a zero order reaction is a chemical reaction that occurs regardless of the reactant's concentration.

The rate law of 2A + B→C is

r = k [A]⁰ [B]⁰

For a zero- order reaction

r = k

This is a Short Answer Type Question as classified in NCERT Exemplar

A bimolecular reaction occurs when two particles collide. The product of the concentrations of both elements determines the rate of reaction. If one of the reactants is taken in substantial excess in such a way that its concentration seldom changes, a bimolecular reaction can be kinetically first order.

This is a Long Answer Type Question as classified in NCERT Exemplar

Tell us about the pseudo-first-order reaction. It's the reaction with the highest true rate law, yet it behaves like a first order reaction, but it's more specifically a second order reaction.

As an example, consider the hydrolysis of an ester.

CH₃COOC₂CH₅ + H₂O→CH₃COOH + C₂H₅OH

rate = k [CH₃COOC₂H₅] [H₂O]… (constant)

k1 [CH₃COOC₂H₅]

k = k [H₂O] 

This is a Long Answer Type Question as classified in NCERT Exemplar

Average rate depends upon the change in concentration of reactants or products and the time taken for that change to occur. However, the average rate cannot be used to predict the rate of reaction at a particular instance as it would be constant for the time interval for which it is calculated. 

So, to express the rate at a particular moment of time we determine the instantaneous rate. Itis obtained when we consider the average rate at the smallest time interval say dt (i.e. when? t approaches zero).