1: 60 percent / iron powder, HCl / H2O; ethanol / Heating 2: 62 percent / H2SO4, NaNO2, hydrobromic acid, CuBr / acetic anhydride 3: 83 percent / AlCl3 / benzene / 6 h / Ambient temperature View Scheme

sulfuric acid; nitric acid T=20°C;

T=30°C;