The pH of water sample collected from a river was found to be acidic in the range of 3.5 – 4.5. On the banks of the river were several factories that were discharging effluents into the river. The effluents of which one of the following factories is the most likely cause for lowering the pH of river water?

The process which is involved in alcohol distillery is Fermentation. During the process of Fermentation, the products obtained are Ethanol and Lactic acid. Ethanol is oxidized to produce Ethanoic acid. When the effluents are discharged into the river, the presence of acids in the effluents will lower the pH of the water of river. Hence, option ‘d’ is the correct answer.