5. Explain the meaning of the following terms: (a) chromophore (c) spiking (b) auxochrome 6. Nitrite in water can be determined by its reaction with sulphanilimide and N-(1-naphthyl)ethylenediamine to give a pink-coloured complex. Five standard solutions of nitrite were prepared, the pink colour was developed and the absorbances were recorded at 550nm as shown in the table below. (a) Plot a calibration curve from the data given. (b) Determine by interpolation of the calibration curve, the nitrite concentration of an unknown sample which gave an absorbance of 0.035. (c) Using Beer-Lambert law, calculate the molarabsorptivity () assuming that the cell path is 1cm. 7. Explain how UV-VIS spectroscopy can be used to distinguish between CH3CH(OH)CHO and CH3CH2COOH