Chemical Kinetics

A hypothetical reaction A $\to$ 2B proceeds through the following sequence of steps

I. A $\to$C; ${∆}_{\mathrm{r}}\mathrm{H} = {\mathrm{q}}_1$

II. C $\to$D; ${∆}_{\mathrm{r}}\mathrm{H} = {\mathrm{q}}_2$

III. $\frac{1}{2}\mathrm{D}$ $\to$ B; ${∆}_{\mathrm{r}}\mathrm{H} = {\mathrm{q}}_3$

The heat of hypothetical reaction is

• q₁ + q₂ - 2q₃

• q₁ + q₂ + 2q₃

• q₁ + 2q₂ - 2q₃

• q₁ - q₂ + 2q₃

Look at the graph,

Choose the correct equation from the following which best suited to the above graph

• [A_t] = [A]₀ -Kt

• [A_t] = [A]₀ + Kt

• [A_t] = [A₀]e^-Kt

• [A_t] = Kt² + [A₀]

Observe the following reaction

2A + B $\to$ C

The rate of formation of C is 2. 2 x 10^-3 mol L^-3 min^-1. What is the value of $-\frac{\mathrm{d}\left[\mathrm{A}\right]}{\mathrm{dt}}$ (in mol L^-1 min^-1)?

• $2.2 \times {10}^{-3}$

• $1.1 \times {10}^{-3}$

• $4.4 \times {10}^{-3}$

• $5.5 \times {10}^{-3}$

Which of the following is an example for heterogeneous catalysis reaction?

• 2SO₂(g) + O₂ $\stackrel{\mathrm{NO}\left(\mathrm{g}\right)}{\to }$ 2SO₃(g)

• Hydrolysis of aqueous sucrose solution in the presence of a aqueous mineral acid

• 2H₂O₂ (l) $\stackrel{\mathrm{Pt}\left(\mathrm{s}\right)}{\to }$ 2H₂O₂(l) + O₂(g)

• Hydrolysis of liquid in the presence of aqueous mineral acid

A hypothetical reaction

X₂ + Y₂ $\to$2XY follows the following mechanism

X₂ $\rightleftharpoons$ X + X .... fast

X + Y₂ $\to$ XY + Y .... slow

X + Y $\to$XY .... fast

The order of overall reaction is

• 2

• $\raisebox{1ex}{$3$}\!\left/ \!\raisebox{-1ex}{$2$}\right.$

• 1

• 0

The variation of concentration of the product P with time in the reaction, A $\to$ P is shown in following graph.

The graph between $\frac{-d \left[A\right]}{dt}$ and time will be of the type

The average kinetic energy of an ideal gas per molecule in SI units at 25°C will be

• 6.17 x 10^-21 JK^-1

• 6.17 x 10^-21 JK^-1

• 6.17 x 10²⁰ JK^-1

• 7.16 x 10^-20 JK^-1

For a zero order reaction

• ${\mathrm{t}}_{\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right.} \propto {\mathrm{R}}_0$

• ${\mathrm{t}}_{\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right.} \propto \frac{1}{{\mathrm{R}}_0}$

• ${\mathrm{t}}_{\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right.} \propto {\mathrm{R}}_0^2$

• ${\mathrm{t}}_{\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right.} \propto \frac{1}{{\mathrm{R}}_0^2}$

In the first order reaction, 75% of the reactant gets disappeared in 1.386 h. The rate constant of the reaction is

• 3.0 $\times$10^-3 s^-1

• 2.8 $\times$ 10 ^-4 s^-1

• 17.2 $\times$ 10^-3 s^-1

• 1.8 $\times$ 10^-3 s^-1

2 g of a radioactive sample having half-life of 15 days was synthesised on 1st Jan 2009. The amount of the sample left behind on 1st March, 2009 (including both the days) is

• 0 g

• 0.125 g

• 1 g

• 0.5 g