Benzenediazonium chloride, C₆H₅N₂Cl, decomposes in water as shown in the following equation. C₆H₅N₂Cl(aq) + H₂O(l) → C₆H₅OH(aq) + N₂(g) + HCl(aq) A solution of 0.0750 moldm⁻³ of C₆H₅N₂Cl(aq) decomposes at a constant temperature of 50°C. The volume of nitrogen gas, N₂(g), collected is recorded every 5 minutes for 45 minutes. Using this method, a student obtains the graph shown in Fig. 2.1. [Figure 2.1] Another student investigates the effect of changing the concentration of C₆H₅N₂Cl(aq) at 50°C. He measures the time taken to collect 0.0150 dm³ of N₂(g) and calculates the rate of N₂ production by dividing 0.0150 dm³ by the time taken. The results are shown in Table 2.1. Table 2.1 | concentration of C₆H₅N₂Cl(aq) / moldm⁻³ | time taken to collect 0.0150 dm³ of N₂/s | rate of N₂ production /dm³s⁻¹ | |---|---|---| | 0.500 | 21 | | | 0.400 | 33 | | | 0.300 | 48 | | | 0.200 | 64 | | | 0.100 | 122 | | C₆H₅N₂Cl is used in the manufacture of synthetic dyes. A student prepares a sample of the dye using the reaction scheme shown in Fig. 2.2. [Figure 2.2] In step 1, phenylamine, C₆H₅NH₂, is converted into C₆H₅N₂Cl. In step 2, C₆H₅N₂Cl is reacted with more C₆H₅NH₂ to produce the solid dye, which is then filtered.