Properties of water equal to that of the hydrogen ion (), which gives a pH of 7 at 25 °C. Action of water on rock over long periods of time typically leads to weathering and water erosion, physical processes that convert solid rocks and minerals into soil and sediment, but under some conditions chemical reactions with water occur as well, resulting in metasomatism or mineral hydration, a type of chemical alteration of a rock which produces clay minerals. It also occurs when Portland cement hardens. Water ice can form clathrate compounds, known as clathrate hydrates, with a variety of small molecules that can
Water crisis in the Democratic Republic of the Congo person were estimated at 7 m³/person/year in 2014, which indicate only a small level of water resource mobilization (less than 1 percent). Water use per capita in the DRC is considerably lower than in many arid Sahel countries, which experience a physical water scarcity problem. Water is mainly utilized for domestic purposes, comprising 52 percent of total water withdrawals in the DRC. Agriculture accounts for 32 percent of total water withdrawals, followed by industry with 16 percent. Fisheries, hydropower generation and navigation are other important water uses in the DRC, which are typically not included in water use statistics. Water