" /> -->

#### Chemical Kinetics Two Marks Question

12th Standard EM

Reg.No. :
•
•
•
•
•
•

Chemistry

Time : 00:45:00 Hrs
Total Marks : 30
15 x 2 = 30
1. Define average rate and instantaneous rate

2. Define rate law and rate constant

3. Derive integrated rate law for a zero order reaction A$\longrightarrow$ product

4. Explain the effect of catalyst on reaction rate with an example

5. The rate law for a reaction of A, B and C has been found to be rate =k[A]2[B][L]3/2 How would the rate of reaction change when
(i) Concentration of [L] is quadrupled
(ii) Concentration of both [A] and [B] are doubled
(iii) Concentration of [A] is halved
(iv) Concentration of [A] is reduced to $\left( 1/3 \right)$ and concentration of [L] is quadrupled.

6. For a reaction A + B ⟶ C, the rate of the reaction is denoted $\frac { -dA }{ dt }$ or $\frac { -dB }{ dt }$ or $\frac { +dC }{ dt }$. State the significance of plus and minus sign.

7. Rate of chemical reaction is not uniform throughout. Justify you answer:

8. H2(g) + Cl2(g) $\overset { hv }{ \longrightarrow }$ 2HCl(g). The reaction proceeds with a uniform rate throughout. What do you conclude?

9. The decomposition reaction of ammonia gas on platinum surface has a rate constant R = 2.5 X 10-4mol L-1. What is the order of the reaction.

10. The reaction A + 2B ⟶ C obeys the rate equation. Rate = $K{ \left[ A \right] }^{ \frac { 1 }{ 2 } }{ \left[ B \right] }^{ \frac { 3 }{ 2 } }$ What is the order of the reaction?

11. How does the value of rate constant vary with reactant constant.

12. In a reaction, 2A $\longrightarrow$ products, the concentration of A decreases from 0.5 mol L-1 to 0.4 mol L-1 in 10 minutes. Calculate the rate during this interval?

13. Consider the oxidation of nitric oxide to form NO2
2NO(g) + O2(g) ➝2NO (g)
(a). Express the rate of the reaction in terms of changes in the concentration of NO,O2 and NO2.
(b). At a particular instant, when [O2] is decreasing at 0.2 mol L−1s−1 at what rate is [NO2] increasing at that instant?

14. What is the order with respect to each of the reactant and overall order of the following reactions?
a) 5Br-(aq)+BrO3-(aq)+6H+(aq) ➝3Br2(l)+3H2O(l)
The experimental rate law is
Rate = k [Br−][BrO3][H+]2
b) CH3CHO(g)$\overset { \Delta }{ \longrightarrow }$ CH4(g)+CO(g) the experimental rate law is
Rate =K[CH3CHO]$\frac{3}{2}$

15. The rate of the reaction X+2y⇾ product is 4x10-3 mol L-1S-1, if [X]=[Y]=0.2M and rate constant at 400K is 2x10-2s-1, What is the overall order of the reaction