What is the titration invented by the Danish chemist famous for the concept of pH used for?
S. P. L. Sørensen Søren Peder Lauritz Sørensen (9 January 1868 – 12 February 1939) was a Danish chemist, famous for the introduction of the concept of pH, a scale for measuring acidity and alkalinity. He was born in Havrebjerg, Denmark.
Xerography Xerography or electrophotography is a dry photocopying technique. Its fundamental principle was invented by Hungarian physicist Pál Selényi and based on Selényi's publications Chester Carlson applied for and was awarded U.S. Patent  on October 6, 1942. The technique was originally called electrophotography. It was later renamed xerography—from the Greek roots ξηρός "xeros", "dry" and -γραφία "-graphia", "writing"—to emphasize that, unlike reproduction techniques then in use such as cyanotype, this process used no liquid chemicals.