What mineral contaminant in laundry water causes unsightly brown rust spots on washed fabrics___________________?
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Answer: A. Iron
Explanation
Dissolved iron minerals present in supply water undergo chemical oxidation upon exposure to air. This oxidation reaction precipitates insoluble iron oxides onto textile fibers during washing cycles. The resulting solid deposits create unsightly reddish-brown rust stains on the washed fabrics. Groundwater frequently contains soluble ferrous bicarbonate minerals picked up from underground aquifers. Oxygen and chlorine bleach act as oxidizing agents that convert ferrous iron to ferric. Water hardness and mineral content dictate the required pretreatment and softening methods.
Commercial laundries install specialized iron filtration systems to protect valuable customer textiles. Residential well water users often experience stained clothing and plumbing fixture discoloration. Specialized chemical rust removers are frequently needed to salvage stained fabric items. Zinc in water supplies rarely causes colored staining issues on washed textile fabrics. Iodine compounds can produce yellowish discolorations but do not form classic rust spots. Bromine water treatments typically leave distinct chemical odors rather than brown precipitates.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
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