Yes the sulphur in the pyrite makes sulphuric acid.
It is generally somewhat acidic but it depends on the geology and climate. In deserts, you often get poor drainage and most of the water comes from below. That tends to make it alkaline. Where there is much organic mater and good drainage and plentiful rain, it tends to be somewhat acidic..
Kevin A. Morin has written: 'Control of acidic drainage in layered waste rock at the Samatosum minesite' -- subject(s): Control, Acid mine drainage
Yuanfang Deng has written: 'Kinetic study of ozone decomposition in acidic aqueous solution and the effect of various species and materials on the rate of ozone decomposition' -- subject(s): Ozone, Chemistry, Decay
I dont know why are you asking?
slightly acidic, low calcium, good drainage
soil
Lemons are sensitive to cold. They like acidic soil. Lemons can be excellent houseplants as long as they have good drainage.
acidic and alkaline
Yes and no. What the corkscrew willow tree [Salix matsudana 'Tortuosa'] prefers is well drained soil. So if the soil has good drainage, and there's no other environmental stress, then the tree can handle a range of soils. Specifically, it's capable of growing in clayey, loamy or sandy soils. It's capable of handling soil pH levels that are acidic or alkaline. But the key here is good drainage.
Soil is nutrient-poor and acidic. Decomposition is rapid and soils are subject to heavy leaching.
Buffers are important because they control the PH or "acidic" balance.
The drained material contains acidic materials which are highly reactive towards Iron and Iron is easily corroded by water and oxygen so iron is not suitable for drainage pipes.