Which of the toxic heavy metals is found in modern tannery industries ?
A. Nickel
B. Zinc
C. Chromium
D. Lead
Answer: Option C
Solution(By Examveda Team)
Chromium is mainly found in waste from the chrome tanning process; it occurs as part of the retanning system and is displaced from leathers during retanning and dyeing processes. This chrome is discharged from processes in soluble form; however, when mixed with tannery waste waters from other processes (especially if proteins are present), the reaction is very rapid. Precipitates are formed, mainly protein-chrome, which add to sludge generation. If chrome discharges are excessive, the chromium might remain in the solution. Even in low concentrations, it has a toxic effect upon daphnia, thus disrupting the food chain for fish life and possibly inhibiting photosynthesis.Related Questions on Chemistry
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A. Greenhouse effect
B. Fire in coal mines
C. Dry farming
D. Monsoon
E. Trade winds
The nucleus of an atom consists of
A. electrons and neutrons
B. electrons and protons
C. protons and neutrons
D. All of the above
The number of moles of solute present in 1 kg of a solvent is called its
A. molality
B. molarity
C. normality
D. formality
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