Project ForgeChemical Technology
Inorganic Chemical Industries
GATE 2010
Medium
In the manufacture of caustic soda from brine, which ONE of the following statements is TRUE?
- AThe membrane cell CANNOT produce concentrated NaOH solution, and CANNOT tolerate calcium and magnesium ions in the feed brine
- BThe membrane cell CANNOT produce concentrated NaOH solution, but CAN tolerate calcium and magnesium ions in the feed brine
- The membrane cell CAN produce concentrated NaOH solution, but CANNOT tolerate calcium and magnesium ions in the feed brine
- DThe membrane cell CAN produce concentrated NaOH solution, and CAN tolerate calcium and magnesium ions in the feed brine
Explanation
The membrane cell produces relatively concentrated, high-purity NaOH directly, but its ion-exchange membrane is easily fouled/damaged by hardness ions (Ca²⁺, Mg²⁺), so it requires very pure brine and cannot tolerate these ions.
Source: GATE CH 2010 (2010)
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