Question

The pH of water sample collected from a river was found to be acidic in the range of 35 – 45 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 most likely to cause low pH of river water? [NCERT Exemplar]
(a) Soap and detergent factory
(b) Lead battery manufacturing factory
(c) Plastic cup manufacturing factory
(d) Alcohol distillery

Answer 1

Lead battery manufacturing company is the right

answer

Answer 2

Answer:

The correct answer is : (b) Lead battery manufacturing factory.

Explanation:

• The question states the pH of water in the river is around 3.5 to 4.5

• Soap has a pH of around 9 while detergent has a pH of around 5.5.
• Lead battery manufacturing factory utilises sulphuric acid as an electrolyte. The pH of sulphuric acid is around 2.
• Plastics are synthetic hydrocarbons and are made from crude oils that are insoluble in water and hence lack acidity or alkalinity.
• Alcohol can act both as a weak base and a weak acid. It has a pH value that ranges around 7.
• The pH of lead battery (2) is close to the pH of the effluent water that is released into the river (3.5), so the low pH of the river water is caused by the effluents released from the lead battery manufacturing factory.