Chemical Kinetics

<p><strong>Which of the following graphs represents exothermic reaction?</strong></p> <div> <div><picture><source srcset="https://images.shiksha.com/mediadata/images/articles/1745907195phprK1uCt_480x360.jpeg" media="(max-width: 500px)"><img src="https://images.shiksha.com/mediadata/images/articles/1745907195phprK1uCt.jpeg" alt="" width="191" height="364"></picture></div> <div> <div><picture>A. (a) only</picture></div> <div>B. (b) only</div> <div>C. (c) only</div> <div> <p>D. (a) and (b) only</p> </div> </div> </div>

Which of the following expressions is correct for the rate of reaction given below?

5Br - (aq) + BrO₃ - (aq) + 6H + (aq)→3Br₂(aq) + 3H₂O(l)

A. $\frac{\mathbf{\Delta }\left[\mathbf{B}\mathbf{r}\right]}{\mathbf{\Delta }}$ = 5 $\frac{\mathbf{\Delta }\left[{\mathbf{H}}^{+}\right]}{\mathbf{\Delta }\mathbf{t}}$

B. $\frac{\mathbf{\Delta }\left[\mathbf{B}\mathbf{r}\right]}{\mathbf{\Delta }}$ = $\frac{6}{5}$ $\frac{\mathbf{\Delta }\left[{\mathbf{H}}^{+}\right]}{\mathbf{\Delta }\mathbf{t}}$

C. $\frac{\mathbf{\Delta }\left[\mathbf{B}\mathbf{r}\right]}{\mathbf{\Delta }}$ = $\frac{5}{6}$ $\frac{\mathbf{\Delta }\left[{\mathbf{H}}^{+}\right]}{\mathbf{\Delta }\mathbf{t}}$

D. $\frac{\mathbf{\Delta }\left[\mathbf{B}\mathbf{r}\right]}{\mathbf{\Delta }}$ = 6 $\frac{\mathbf{\Delta }\left[{\mathbf{H}}^{+}\right]}{\mathbf{\Delta }\mathbf{t}}$

Which of the following statements is correct?

A. The rate of a reaction decreases with passage of time as the concentration of reactants decreases.

B. The rate of a reaction is same at any time during the reaction.

C. The rate of a reaction is independent of temperature change.

D. The rate of a reaction decreases with increase in concentration of reactants.

Consider the graph given in Fig. 4.2. Which of the following options does not show instantaneous rate of reaction at 40^th second?

I. $\frac{{\mathbf{V}}_5-{\mathbf{V}}_2}{50-30}$

II. $\frac{{\mathbf{V}}_4-{\mathbf{V}}_2}{50-30}$

III. $\frac{{\mathbf{V}}_3-{\mathbf{V}}_2}{40-30}$

IV. $\frac{{\mathbf{V}}_3-{\mathbf{V}}_1}{40-20}$

Which of the following statements is not correct about order of a reaction

A. The order of a reaction can be a fractional number.

B. Order of a reaction is experimentally determined quantity.

C. The order of a reaction is always equal to the sum of the stoichiometric coefficients of reactants in the balanced chemical equation for a reaction.

D. The order of a reaction is the sum of the powers of molar concentration of the reactants in the rate law expression. 

A graph of volume of hydrogen released vs time for the reaction between zinc and dil. HCl is given in Fig. 4.2. Based on this mark the correct option   

Consider the Arrhenius equation given below and mark the correct option.

k = Ae

A. Rate constant increases exponentially with increasing activation energy and decreasing  temperature.

B. Rate constant decreases exponentially with increasing activation energy and decreasing temperature.

C. Rate constant increases exponentially with decreasing activation energy and decreasing temperature.

D. Rate constant increases exponentially with decreasing activation energy and increasing temperature.

According to Arrhenius equation rate constant k is equal to A^e - . Which of the following options represents the graph of in k vs  .

Consider a first order gas phase decomposition reaction given below:

A(g) → B(g) + C(g) 

The initial pressure of the system before decomposition of A waspt . After lapse of time ‘t’, total pressure of the system increased by x units and became ‘t’ the rate constant k for the reaction is given as _________.

Consider Fig. 4.1 and mark the correct option.