Tag: science & technology

Thomas Alva Edison was called the 'Wizard of Menlo Park' because he established his famous laboratory and invention factory in Menlo Park, New Jersey, where he developed many revolutionary inventions including the phonograph and the practical electric light bulb. George Bernard Shaw was a playwright, Charlie Chaplin was a comedian, and William Harvey discovered blood circulation.

Kirkpatrick MacMillan, a Scottish blacksmith, invented the first bicycle with foot pedals in 1839. Earlier versions like Baron von Drais's 'running machine' (1817) had no pedals - you pushed with your feet on the ground. Thomas Edison invented the light bulb and phonograph, Henry Ford developed the assembly line for automobiles, and Gottlieb Daimler pioneered internal combustion engines.

There are only two common words in English starting with 'su' pronounced as 'sh': 'sugar' and 'sure'. In 'sugar', the 'su' is pronounced 'shu', and in 'sure', it's pronounced 'shur'. This is a linguistic irregularity in English where 'su' normally makes the 'su' sound (as in 'sun' or 'supper'). All other 'su' words maintain the regular 'su' pronunciation.

Water gas is a fuel gas consisting mainly of carbon monoxide (CO) and hydrogen (H2), produced by passing steam over red-hot coke. It was historically important for industrial heating and lighting. Option A incorrectly states carbon dioxide, Option B has a typo and incorrect chemistry, and Option D describes the reactants, not the product.

Oleum is fuming sulfuric acid, which is concentrated sulfuric acid dissolved in excess sulfur trioxide (SO3). It's called 'fuming' because it releases SO3 vapors that form white fumes when exposed to moist air. Options A and C are incorrect because oleum is more concentrated than regular concentrated H2SO4 and is certainly not dilute.

Sulfuric acid is manufactured by the Contact process, which involves catalytic oxidation of SO2 to SO3 over vanadium pentoxide catalyst, followed by absorption in concentrated H2SO4 to form oleum. The name 'Contact' refers to the solid catalyst that 'contacts' the reacting gases. The other options (explosive, emission, fission, chain) are not related to H2SO4 manufacturing.

Chloroform's IUPAC name is trichloromethane (CHCl3), indicating it has one carbon atom bonded to three chlorine atoms and one hydrogen atom. Option A is incorrect as chlorofluorocarbons (CFCs) are different compounds. Options B and D refer to two-carbon compounds (ethane/ethylene), not chloroform.

Silicon is a semiconductor because its electrical conductivity is between that of conductors (like metals) and insulators (like ceramics). Its conductivity can be controlled by doping, making it essential for modern electronics. Silicon is neither a good conductor nor a good insulator in its pure form.

Hydrocarbons contain only carbon and hydrogen atoms, both of which share electrons to form bonds. Carbon is tetravalent and forms covalent bonds by sharing its four valence electrons with other atoms. Electrovalent bonds involve electron transfer (ionic), while metallic bonds occur in metals, not organic molecules.

Helium is a rare gas (noble gas) - Group 18 elements known for being chemically inert due to their complete valence electron shells. Lithium is an alkali metal (Group 1), lanthanum is a lanthanide, and zirconium is a transition metal. Rare gases are called 'rare' because they exist in trace amounts in Earth's atmosphere.