Question

Silicon carbide (SiC) is commonly manufactured in an electric furnace by reacting:

• A. Silica with limestone
• B. Silica with coke
• C. Alumina with coke
• D. Lime with graphite

Hint:

Logic Tip: Look at the name "Silicon Carbide." You need a "Silicon" source (Silica) and a "Carbon" source (Coke) to make it happen!

Answer 1

The Correct Option is B

Concept:
The industrial synthesis of Silicon Carbide (SiC), also known as carborundum, is achieved via the Acheson process. This involves a high-temperature solid-state reaction between a silicon source and a carbon source.

Step 1: The chemical formula for silicon carbide is SiC. Therefore, the raw materials must provide elemental Silicon (Si) and elemental Carbon (C).

Step 2: Silica (Silicon Dioxide, $SiO_2$) is the most abundant and economically viable source of silicon for this industrial process.

Step 3: Petroleum coke is a highly pure, carbon-rich solid material derived from oil refining, making it the ideal reducing agent and carbon source.

Step 4: Limestone ($CaCO_3$) and Alumina ($Al_2O_3$) do not provide the necessary Si or C atoms. Graphite is too expensive compared to coke for bulk manufacturing.

Step 5: When silica and coke are reacted in an electric resistance furnace at extreme temperatures ($1600-2500^{\circ}C$), they form Silicon Carbide and Carbon Monoxide gas ($SiO_2 + 3C \rightarrow SiC + 2CO$).