An industrial chemist must continuously monitor the concentration of trace quantities…
CHEMISTRY · Multi-part · A Level · Chemistry · Organic analysis and spectroscopy · Organic analysis and spectroscopy
Problem
An industrial chemist must continuously monitor the concentration of trace quantities of ammonia, NH₃(g), in the effluent stream of a fertilizer plant. The monitoring system must (1) provide real-time data with a response time under one minute, (2) distinguish ammonia from other common effluent gases such as N₂, O₂, CO₂, and H₂O vapor, and (3) operate reliably in a temperature range of 300–350 K.
The plant can install only one spectroscopic instrument because of budget limits. Available instruments include a microwave spectrometer, an IR spectrometer equipped with a gas cell, and a UV-Vis spectrometer with fiber-optic probes.
Answer the following questions.
(a) Identify the single spectroscopic technique that best satisfies all three operational requirements. State the region of the electromagnetic spectrum in which this technique operates.
(b) Provide two specific reasons, grounded in molecular properties of ammonia and the listed interferences, that support your choice in part (a).
(c) Explain one practical limitation the chosen technique might encounter under the stated operating conditions, and propose one modification or procedural control that would mitigate this limitation.