Which method can be used to neutralize acidic wastewater?

Feeding in soda ash is the correct method to neutralize acidic wastewater. Soda ash, chemically known as sodium carbonate, is an alkaline compound that reacts with acids to neutralize them. When soda ash is added to acidic wastewater, it raises the pH level, effectively neutralizing the acid and making the wastewater less harmful before it is treated or discharged. This process is important in wastewater management as it helps in preventing corrosion in pipes and other equipment and ensures that the discharge meets environmental regulations.

The other options do not effectively neutralize acidity. Sodium chloride is a neutral salt that does not have any significant effect on pH. Hydrochloric acid would further increase acidity rather than neutralizing it. Potash, primarily potassium carbonate, can have some alkaline properties, but it is not as effective as soda ash for directly neutralizing strong acids in wastewater. Thus, using soda ash is the most effective and widely accepted method for this purpose.