Question

Which of the following is used in the extraction of silver? (a) \(\mathrm{NaCN}\) (b) \(\mathrm{Na}_{2} \mathrm{SO}_{4}\) (c) \(\mathrm{Na}_{2} \mathrm{CO}_{3}\) (d) \(\mathrm{NaCl}\)

Short answer

(a) \(\mathrm{NaCN}\) is used in the extraction of silver.

Step-by-step solution

Examine the Options

First, we need to examine which of these chemicals can be used in the extraction of silver. The extraction of silver commonly involves processes where silver is dissolved and later precipitated or recovered.

Identify Key Extraction Process

In the process of extracting silver, a key method is the cyanide process, also known as silver cyanidation. This process uses sodium cyanide ( \( \mathrm{NaCN} \ \) to dissolve silver from its ores.

Analyze the Function of Cyanide

In the cyanide process, silver is converted into a soluble silver cyanide complex. This method allows for efficient separation of silver from its ore, making sodium cyanide ( \( \mathrm{NaCN} \)) a crucial reagent in silver extraction.

Conclude With the Correct Option

Evaluate which option is used in the cyanide process for extracting silver. Sodium cyanide ( \( \mathrm{NaCN} \)is the correct chemical for this process.

Key concepts

Cyanide Process

The cyanide process is a vital technique in the extraction of precious metals, primarily gold and silver. It involves using cyanide, a potent chemical, to separate silver from its ore. This method is highly effective in transforming silver ores into a soluble form, which allows for easier recovery. The process often starts with crushing the silver ore. By crushing, the surface area of the ore increases, facilitating a more effective reaction with cyanide.

Once the ore is prepared, it's mixed with a solution containing cyanide ions. The cyanide solution interacts chemically with the silver, forming a soluble complex ion. This conversion into a soluble form is central to the process as it allows silver to be separated from other minerals present in the ore.

The dissolved silver is then recovered. This can happen by processes such as precipitation, where another chemical is introduced to separate silver from the cyanide solution. Often, zinc is added to displace silver, precipitating it out of the solution.

Sodium Cyanide

Sodium cyanide is a key player in the extraction of silver. It is a white, water-soluble compound, well-regarded for its role in mining. The chemical formula for sodium cyanide is \( \text{NaCN} \), which is used extensively to extract silver and gold from their ores. Sodium cyanide dissolves easily in water, forming a solution rich in cyanide ions.

In extraction, solid silver reacts with sodium cyanide to form a complex cyanide ion. The reaction between silver and sodium cyanide results in the breakthrough compound, silver cyanide, which is highly soluble. The use of sodium cyanide not only makes mining more efficient but also allows for the extraction of silver from low-grade ores.

The safety and environmental implications of using sodium cyanide are important considerations. Cyanide is toxic, so rigorous handling procedures and disposal practices are crucial to minimize harm to workers and the environment. Regular monitoring, closed handling systems, and strict adherence to regulations ensure safety in mining operations.

Silver Cyanidation

Silver cyanidation is a chemical process that increases the efficiency of silver extraction from its ores. It encompasses both the dissolution of silver using cyanide and its subsequent recovery. The process begins when silver ore is mixed with a cyanide solution. This leads to the formation of a silver cyanide complex that is soluble, making it easier to isolate the silver.

The main reactions involved in silver cyanidation start with metallic silver converting to silver cyanide. This reaction occurs because the cyanide ion has a high affinity for silver, forming a stable complex. Once in solution, the complex can be separated from the other constituents of the ore.

Recovery of silver from the cyanide solution often involves zinc. Zinc is more reactive than silver, and its introduction into the solution displaces silver from the complex, letting it precipitate out. This method ensures most of the silver is reclaimed efficiently, making cyanidation an especially effective technique in the mining industry.