2HgCl2(aq) + C2O42–(aq) → 2Cl–(aq) +2CO2(g) + Hg2Cl2(s)

The above reaction was studied by the method of initial rates and the following results were obtained:

[HgCl2] (M)

[C2O42–] (M)

Initial Rate (M/min)

0.105

0.15

1.8x10–5

0.105

0.30

7.2x10–5

0.0525

0.30

3.6 x10–5

0.0525

0.15

9.0x10–6

How would you describe the kinetics of this reaction? What is the rate constant?

first-order wrt HgCl2, second-order wrt C2O42–, third-order overall

k = 7.6x10–3 M–2min–1

first-order with respect to (wrt) HgCl2, first-order wrt C2O42–, second-order overall

k = 1.1x10–3 M–1min–1

zero-order wrt HgCl2, second-order wrt C2O42–, second-order overall

k = 5.4x10–5 Mmin–1

first-order wrt HgCl2, second-order wrt C2O42–, second-order overall

k = 4.3x10–8 M–2min–1

Respuesta :

Explanation:

Expression for rate of the given reaction is as follows.

             Rate = k[HgCl_{2}]x [C_{2}O^{2-}_{4}]y[/tex]

Therefore, the reaction equations by putting the given values will be as follows.

       [tex]1.8 \times 10^{-5} = k[0.105]x [0.15]y[/tex] ............. (1)

       [tex]7.2 \times 10^{-5} = k [0.105]x [0.30]y[/tex] ........... (2)

       [tex]3.6 \times 10^{-5} = k [0.0525]x [0.30]y[/tex] ............ (3)

Now, solving equations (1) and (2) we get the value of y = 2. Therefore, by solving equation (2) and (3)  we get the value of x = 1.

Therefore, expression for rate of the reaction is as follows.

     Rate = [tex]k[HgCl_{2}]x [C_{2}O^{2-}_{4}]y[/tex]

          Rate = [tex]k [HgCl2]1 [C_{2}O^{-2}_{4}]2[/tex]

Hence, total order = 1 + 2 = 3

According to equation (1),

               [tex]1.8 \times 10^{-5} = k[0.105]x [0.15]y[/tex]  

            [tex]1.8 \times 10^{-5} = k [0.105]1 [0.15]2[/tex]  

                      k = [tex]7.6 \times 10^{-3} M^{-2} min^{-1}[/tex]  

Thus, we can conclude that rate constant for the given reaction is [tex]7.6 \times 10^{-3} M^{-2} min^{-1}[/tex].