MCQ Detailed View

Silver nitrate (AgNO₃) is one of the most important reagents used in analytical chemistry laboratories. It is widely employed for the detection and determination of halide ions such as chloride (Cl⁻), bromide (Br⁻), and iodide (I⁻). When a solution containing halide ions is treated with silver nitrate, it produces characteristic precipitates of silver halides. For example, silver chloride (AgCl) is white, silver bromide (AgBr) is pale yellow, and silver iodide (AgI) is yellow. These distinct colors help in the qualitative identification of halides.

This reaction occurs because silver ions (Ag⁺) readily combine with halide ions to form insoluble salts. The general equation can be written as:
Ag⁺(aq) + X⁻(aq) → AgX(s),
where X⁻ represents Cl⁻, Br⁻, or I⁻.

Silver nitrate is not used for detecting alkali metals, because their salts are usually soluble and do not form characteristic precipitates with AgNO₃. It is also not a reagent for aldehydes or ketones, as these functional groups are tested using specific reagents like Fehling’s solution, Tollens’ reagent, or 2,4-DNP. Instead, silver nitrate remains specific and highly reliable for halide detection in both qualitative and quantitative analysis.

In addition to halide determination, silver nitrate also plays a role in gravimetric analysis, where the mass of the silver halide formed is measured to calculate the amount of halide present in a sample. This makes it an important reagent in classical analytical chemistry.

The ability of AgNO₃ to give clear, visible results makes it a fundamental chemical in laboratory analysis. Its use in detecting halides remains one of the most common applications taught in basic chemistry courses.