A gas syringe contains a mixture of dinitrogen tetroxide (N2O4\text{N}_2\text{O}_4N2O4, colourless) and nitrogen dioxide (NO2\text{NO}_2NO2, brown) at a constant temperature in a sealed system. The system reaches a state of dynamic equilibrium:
N2O4(g)⇌2NO2(g) \text{N}_2\text{O}_4(\text{g}) \rightleftharpoons 2\text{NO}_2(\text{g}) N2O4(g)⇌2NO2(g)Which of the following statements correctly describes the system at dynamic equilibrium?
The concentration of NO2(g)\text{NO}_2(\text{g})NO2(g) is exactly double the concentration of N2O4(g)\text{N}_2\text{O}_4(\text{g})N2O4(g) due to the 1:21:21:2 stoichiometric ratio.
The rates of the forward and reverse reactions are equal, so the intensity of the brown colour remains constant.
The individual molecules of N2O4\text{N}_2\text{O}_4N2O4 and NO2\text{NO}_2NO2 stop reacting once equilibrium is established.
The forward reaction occurs at a higher rate because gaseous molecules are being produced in a 1:21:21:2 ratio.
Practise Edexcel GCSE Chemistry Dynamic equilibria with exam-style questions for Foundation and Higher tier. 30 questions, matched to the Edexcel GCSE Chemistry (1CH0) specification and written in Paper 1 and Paper 2 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.
