In chemistry, an alkali is a basic, ionic salt of an alkali metal or alkaline earth metal chemical element. An alkali can be defined as a base that dissolves in water. A solution of a soluble base has a pH greater than 7.0. The adjective alkaline is and alkalescent less used in English as a synonym for basic for bases soluble in water; this broad use of the term is to have come about because alkalis were the first bases known to obey the Arrhenius definition of a base, they are still among the most common bases. The word "alkali" is derived from Arabic al qalīy, meaning the calcined ashes, referring to the original source of alkaline substances. A water-extract of burned plant ashes, called potash and composed of potassium carbonate, was mildly basic. After heating this substance with calcium hydroxide, a far more basic substance known as caustic potash was produced. Caustic potash was traditionally used in conjunction with animal fats to produce soft soaps, one of the caustic processes that rendered soaps from fats in the process of saponification, one known since antiquity.

Plant potash lent the name to the element potassium, first derived from caustic potash, gave potassium its chemical symbol K, which derived from alkali. Alkalis are ones which form hydroxide ions when dissolved in water. Common properties of alkaline aqueous solutions include: Moderately concentrated solutions have a pH of 7.1 or greater. This means. Concentrated solutions are caustic. Alkaline solutions are slippery or soapy to the touch, due to the saponification of the fatty substances on the surface of the skin. Alkalis are water-soluble, although some like barium carbonate are only soluble when reacting with an acidic aqueous solution; the terms "base" and "alkali" are used interchangeably outside the context of chemistry and chemical engineering. There are various more specific definitions for the concept of an alkali. Alkalis are defined as a subset of the bases. One of two subsets is chosen. A basic salt of an alkali metal or alkaline earth metal Any base, soluble in water and forms hydroxide ions or the solution of a base in water.

The second subset of bases is called an "Arrhenius base". Alkali salts are soluble hydroxides of alkali metals and alkaline earth metals, of which common examples are: Sodium hydroxide – called "caustic soda" Potassium hydroxide – called "caustic potash" Lye – generic term for either of two previous salts or their mixture Calcium hydroxide – saturated solution known as "limewater" Magnesium hydroxide – an atypical alkali since it has low solubility in water Soils with pH values that are higher than 7.3 are defined as being alkaline. These soils can occur due to the presence of alkali salts. Although many plants do prefer basic soil, most plants prefer a mildly acidic soil, alkaline soils can cause problems. In alkali lakes, evaporation concentrates the occurring carbonate salts, giving rise to an alkalic and saline lake. Examples of alkali lakes: Alkali Lake, Lake County, Oregon Baldwin Lake, San Bernardino County, California Bear Lake on the Utah–Idaho border Lake Magadi in Kenya Lake Turkana in Kenya Mono Lake, near Owens Valley in California Redberry Lake, Saskatchewan Summer Lake, Lake County, Oregon Tramping Lake, Saskatchewan Alkali metals Alkaline earth metals Base

500 is the natural number following 499 and preceding 501. 500 is a Harshad number in bases 5, 6, 10, 11, 13, 15 and 16. Five hundred is the number that many NASCAR races use at the end of their race names, to denote the length of the race; the longest advertised distance of the IndyCar Series and its premier race, the Indianapolis 500. The Fiat 500, an Italian car, or a number of cars in the United States built by Ford: the Ford Five Hundred, Galaxie 500 and Custom 500. An American alternative rock band is named Galaxie 500, the Canadian rock band Galaxie used the name Galaxie 500. North Carolina rock band Fetchin Bones released an album in 1987 called Galaxy 500. A name of two different card games, see 500 for the trick taking game and 500 Rum for the rummy game. Days of Summer is a 2009 film directed by Marc Webb an outdoor ball/disc game, see 500 an HTTP status code for Internal Server Error an SMTP status code meaning a syntax error has occurred due to unrecognized command the years AD 500, 500 BC. the winning permillage of a sports team with equal numbers of wins and losses.

Such teams are referred to as "500 teams". "500 Miles" is a folk song made popular in the world during the 1960s. "Reservoir 500", northeast of Ürümqi, the end point of the Irtysh–Ürümqi Canal in China "I'm Gonna Be," from Scottish band The Proclaimers has become popular since its 1988 release on their album Sunshine on Leith, featuring in many shows and films, including Benny and Joon and How I Met Your Mother. Monkey 501 = 3 × 167, it is: the sum of the first 18 primes. Palindromic in bases 9 and 20. Country calling code for Belize 502 = 2 × 251 a proposed HTTP status code for indicating server is temporarily overloaded, SMTP status code meaning command not implemented country calling code for Guatemala 503 is: a prime number. A safe prime; the sum of three consecutive primes. The sum of the cubes of the first four primes. A Chen prime an Eisenstein prime with no imaginary part. Proposed HTTP status code indicating a gateway time-out, SMTP status code meaning bad sequence of commands country calling code for El Salvador 504 = 23 × 32 × 7.

It is: a tribonacci number. A semi-meandric number. A refactorable number. A Harshad number in bases 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 15, 16 the SMTP status code meaning command parameter not implemented country calling code for Honduras 505 = 5 × 101, Harshad number in bases 3, 5, 6 model number of Levi's jeans, model number of U-505 This number is the magic constant of n×n normal magic square and n-queens problem for n = 10. New Mexico – Before October 7, 2007, The United States state of New Mexico had a single area code of 505; the state was, still is, referred to as'the 505' in slang. Country calling code for Nicaragua 506 = 2 × 11 × 23, it is: a sphenic number. A square pyramidal number. A pronic number. A Harshad number in bases 4, 10, 12 country calling code for Costa Rica 507 = 3 × 132, Harshad number in bases 13 and 14. Country calling code for Panama 508 = 22 × 127, sum of four consecutive primes, Harshad number in base 13. Country calling code for Saint-Pierre-et-Miquelon 509 is: a prime number.

A Sophie Germain prime, smallest Sophie Germain prime to start a 4-term Cunningham chain of the first kind. A Chen prime. An Eisenstein prime with no imaginary part. A cototient number country calling code for Haiti 510 = 2 × 3 × 5 × 17, it is: the sum of eight consecutive primes. The sum of ten consecutive primes; the sum of twelve consecutive primes. A nontotient. A sparsely totient number. A Harshad number in bases 3, 5, 6, 10, 11, 12, 13, 15, 16 511 = 7 × 73, it is: a Harshad number in bases 3, 5, 7, 10, 13, 15. A palindromic number and a repdigit in bases 2 and 8 5-1-1, a roadway status and transit information hotline in many metropolitan areas of the United States. 512 = 29. It is: a power of two. A cube of 8. A Leyland number. A Dudeney number. A Harshad number in bases 2, 3, 4, 5, 7, 8, 9, 10, 13, 15, 16. Palindromic in bases 7 and 15. 513 = 33 × 19. It is: palindromic in bases 2 and 8 a Harshad number in bases 3, 4, 5, 7, 9, 10, 13, 14, 15, 16 Area code of Cincinnati, Ohio 514 = 2 × 257, it is: a centered triangular number.

A nontotient a palindromic in bases 4, 16, 19 a Harshad number in base 2. 515 = 5 × 103, it is: the sum of nine consecutive primes. A Harshad number in bases 3, 4, 16. 516 = 22 × 3 × 43, it is: nontotient. Untouchable number. Refactorable number. A Harshad number in bases 2, 3, 4, 6, 7, 9, 10, 13, 15, 16. 517 = 11 × 47, it is: the sum of five consecutive primes. A Smith number. A Harshad number in base 12. 518 = 2 × 7 × 37, it is: = 51 + 12 + 83. A sphenic number. A nontotient. An untouchable number. Palindromic and a repdigit in bases 6 and 36. A Harshad number in bases 8, 9, 10, 13, 15. 519 = 3 × 173, it is: the sum of three consecutive primes palindromic in bases 9 and 12. 520 = 23 × 5 × 13. It is: an untouchable number. A palindromic number in base 14. A Harshad number in bases 2, 4, 5, 6, 7, 8, 11, 13, 14, 16. 521 is: a Lucas prime. A Mersenne exponent, i.e. 2521−1 is prime. A Chen prime. An Eisenstein prime with no imaginar

Prem Nazirine Kanmanilla is a 1983 Malayalam crime film, starring Vijay Menon, Maniyanpilla Raju and Sreenivasan, who play as kidnappers of Prem Nazir. Other supporting actors include Mammootty and Nedumudi Venu; the movie shows the Kerala society and its political leadership and how various people behave during such a tragic event. The name may have been based on an older movie Post Man-e Kaananilla in which Prem Nazir played the lead role. A group of frustrated youngsters decides to kidnap the famous Malayalam actor Prem Nazir from one of the film shooting sets; the captured Prem Nazir is taken to a dilapidated home in a dense forest. The kidnappers treat Prem Nazir with due respect and treat him in the best possible manner, given the place where they are. One kidnapper comes from an upper-caste Hindu family, his father worked as the local temple oracle. Though educated, he does not find a good job. Another gang member has a troubled childhood during which his parents were murdered and he had to live as a domestic helper of the murderer.

The kidnap of Prem Nazir is to express their frustration against the cruel society. Kerala is now shocked to hear about this news. Old actresses Kumari are seen watching old movies in which Prem Nazir acted with them. New movie releases have been suspended and old Prem Nazir movies are now played in the theatres. For the movie distributors this is a quick way to make some extra revenue; the producer of the latest movie in which Prem Nazir was acting, is in a bad state. Only two more scenes in his movie were yet to be shot. In desperation he requests Prem Nazir's brother Prem Nawaz to act as a dummy, so that he can somehow complete the movie; the producer, named Innocent, pleads with Prem Nawaz that the movie would get completed, he can release the movie and generate some quick money. His idea is to release the movie; the political scene in the state is in a bad condition. The ruling government of the day is accused of being lax on investigations; the party in the opposition feels that government did not provide adequate protection to Prem Nazir because, Nazir sympathised with the party in opposition.

Demands are made asking the Home Minister to resign. The Home Minister flatly tries to retain his position, he feels there are international agencies out there involved in the kidnapping and so assistance from the central government is required. Meanwhile the state police mobilizes large numbers of police officers from the armed reserve and armed police battalions for a combing operation. At the same time, Prem Nazir, who by had become quite friendly with the kidnappers, manages to convince them of the foolishness of their actions, he advises them to surrender. They soon plan to escape from the forest with a plan to surrender when they are ambushed by a police party; the police whose only aim was to rescue Prem Nazir uses excessive force to capture the kidnappers. They are beaten all the way to the police vehicles and one of them is shot. A dejected Prem Nazir looks on helplessly as he knows that the kidnappers are not hardcore criminals, but he cannot convince the police and the government leadership and the people.

Prem Nazir – Himself Mammootty - Himself Sreenivasan – Kidnapper Maniyanpilla Raju – Kidnapper Vijay Menon – Kidnapper Gangadharan Menon – Kidnapper Shankar – Himself Achankunju – Maran Thilakan – Home Minister Innocent – Innocent, the film producer Santhakumari – Bhargavi Swapna - Pappi Nedumudi Venu - Himself Madhavi - Herself Shanthi Krishna - Herself Menaka - Herself Lakshmi Sheela Prema Innocent, one of the popular comedians in the Malayalam movie, acts as a film producer. In real life, in the 1980s, Innocent was a film producer. Director P. G. Vishwambharan, actors Mammootty, Nedumudi Venu and Prem Nawaz act as themselves in the movie. John Samuel, quite popular anchor for the programme Prathikaranam in Doordarshan Malayalam in early 1990s acted as the Deputy Superintendent of Police investigating this case. Prem Nazirine Kanmanilla on IMDb