Is the rain acidic or alkaline?

Normal rain should be slightly acidic, because the atmosphere contains a lot of CO2, so the normal rain itself is slightly acidic, with a pH of about 5.6. In addition, when the pH value in rainwater is less than 5.6, it is generally called acid rain. In some special cases, rain is affected by many natural phenomena, and the pH value can be changed between 4.6.5, so when the pH value is less than 5.0, it should be regarded as acid rain.

Extended data:

Rain usually occurs in four forms:

1, frontal rain (plum rain): Warm and humid air from the ocean meets cold air from the land. Because cold air is heavy and warm air is light, warm and humid air is forced to rise and condense when it is cold, forming a long and wide rain belt. This is frontal rain.

2. Convective rain: In summer, under the strong sunlight, the warm and humid air in some areas rises sharply, and it condenses when it meets cold to form rain. This is convective rain, which is called "thunderstorm" in meteorology, and we usually call it "explosion". In addition, typhoon rain is also a kind of convective rain.

3. Topographic precipitation: Warm and humid air from the ocean is forced to rise when it meets mountains, and condenses when it meets cold, resulting in rainfall.

4. Typhoon storm: The hot and humid air on the tropical ocean surface rotates and rises strongly in a large range. In the process of rising, the temperature drops rapidly, and a large amount of water vapor condenses into clouds and rain, which is typhoon rain.

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