When CINO₂ reacts with NO an equilibrium is established. CINO2(g) + NO(g) ⇌ NO2(g) + CINO(g) In each CINO₂ molecule the nitrogen atom is bonded to the chlorine atom and bonded to each of the oxygen atoms separately.

1. (a)Draw a 'dot-and-cross' diagram for the CINO₂ molecule.[2]
2. (b)(i)The reaction between CINO2 and NO is first order with respect to each reactant. Write the rate equation for this reaction.[1]
3. (b)(ii)Deduce the units of the rate constant, k, when the concentrations of both gases are measured in moldm⁻³ and the rate is measured in moldm⁻³s⁻¹.[1]
4. (b)(iii)State and explain whether or not the reaction could take place in a single step.[1]
5. (c)(i)An experiment is carried out in which the initial [CINO₂] is 2.0 × 10⁻⁴ moldm⁻³. A large excess of NO is used. The initial rate of reaction is 1.0 × 10⁻⁴ moldm⁻³s⁻¹. The rate of the reaction is assumed to be constant for the first 0.20 seconds. Draw a graph on the grid to show how the concentration of CINO₂ varies for the first 0.20 seconds.[2]
6. (c)(ii)Deduce the concentration of the NO2 product at 0.20 seconds.[1]
7. (c)(iii)After 20 seconds the concentration of CINO2 remains constant. Explain this observation.[1]

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