(i) A road tanker carrying an acid was involved in an accident and its content spilled on the road. At the side of the road, iron drain covers began melting and fizzing as the acid ran over them. A specialist was called to see if the acid actually leaked into the nearby river. (a) Explain how the specialist could carry out a simple test to see if the river water contains some acid or not. (b) The word melting is incorrectly used in the report, Suggest a better name that should have been used. (c) Explain why drain covers began fizzing as the acid rain over them.