1a) The connection between coal-fired plants and poor visibility is such that coal fired plants release huge amounts of water vapour along with the combustion process. Hence, water vapour when cooled in the forest area in the National Park becomes visible as fog, causing the poor visibility.

b) The average pH of rain should be neutral at pH = 7. Therefore, since the average rainfall in Mammoth Cave National Park is 10 times more acidic than natural, the difference in pH will thus be equals to 1. (log(10)). Hence, the estimated pH of rainfall in the park would be 7-1=6.

2a)Hanging laundry to dry instead of using a dryer reduces electricity consumption.By reducing the demand for electricity consumption, electricity production may eventually be reduced as well. As electricity mainly originates from coal burning which produces sulfur dioxide, a contributor to acid rain, the consequent reduction in sulfur dioxide production may thus reduce the production of acid rain.

2b)Walking, cycling or taking public transport instead of driving a personal vehicle will reduce the amount of cars on the road. This will reduce the amount of NOx gas produced from engines in the car. The NOx gas produced contributes to acid rain and reducing the gas will hence reduce acid rain.

2c) Running dishwasher and washing machine with a larger load means that there is a lower frequency of using the dishwasger and washing machine. This will reduce the energy usage in general and reduce the amount of fuel burnt to provide the energy. Therefore lower amount of SOx gas produced in the process and reduces acid rain.

2d) Adding additional insulation on hot water heater and pipes helps to reduce heat loss to the surround and thus lesser energy is required to heat the system up. Lower energy consumption will lead to lower coal burning and lower SOx gas formed.

2e) Buying local product means that there is a lower demand for overseas goods. This means that there is a lower need for airplanes and ships to deliver products across countries. This reduces the amount of NOx gas produced from the engines of airplanes and ship which will contributes to acid rain.

3a)

3b) Acids react with metals to liberate hydrogen. Acids conduct electricity. Acids changes blue litmus paper red. Base conducts electricity. Base changes red litmus paper blue. Base reacts with acid to neutralise their properties, forming water as a product.

4)In general, there is a drop in air quality in Singapore due to various factors such as industrial activities. Recently, Singapore’s air quality standards have fallen below WHO guidelines for three city-related pollutants, which includes pollutants such as sulphur dioxide, ozone and PM10.

One of the issues related to the acid rain in Singapore is the possible wipeout of native species in Singapore. Due to acid rain, the streams in nature reserve become more acidic, thus making the streams become less habitable for aquatic species.

The other issues raised related to acid rain in Singapore is the damage of buildings and statues due to acid rain. Damage is done on the buildings and statues via chemical reactions such as corrosion and rusting. As the result, this will increase the cost of operation for maintenance purpose.

Based on the information provided by NEA, the pollutants which cause acid rain (eg. sulphur dioxide) are released mainly from industries and motor vehicles. Among all industries, the refinery industry contributes the most to sulphur dioxide emission (93.1%). In conclusion, the acid deposition originates mainly from Singapore itself.