General Science Chemistry MCQs
Chemistry Objective (Multiple Choice) General Knowledge Questions & Answers for SSC-CGL, UPPSC, UPSC, NDA, CDS and UPSC Civil Services Prelims Examination
[D] surface charge
Tap water contains ions (due to dissolved impurities) which help in conduction of electricity. Whereas, distilled water does not contain ions, so it can not conduct electricity.
[A] Table salt
[B] Blue Vitriol
[C] Green Vitriol
[D] Baking Soda
Baking soda is chemically sodium bicarbonate (NaHCO3) which does not contain any water of crystallization.
[A] Crystal violet
[B] Aniline blue
Alizarin or 1,2-dihydroxyanthraquinone (also known as Mordant Red 11 and Turkey Red is an organic compound with formula C14 H8 O4 that has been used throughout history as a prominent red dye, principally for dyeing textile fabrics. Historically it was derived from the roots of plants of the madder genus. In 1869, it became the first natural pigment to be duplicated synthetically.
Petroleum, a complex mixture of hydrocarbons that occur in Earth in liquid, gaseous, or solid form. The term is often restricted to the liquid form, commonly called crude oil, but, as a technical term, petroleum also includes natural gas and the viscous or solid form known as bitumen, which is found in tar sands. The liquid and gaseous phases of petroleum constitute the most important of the primary fossil fuels. Liquid and gaseous hydrocarbons are so intimately associated in nature that it has become customary to shorten the expression “petroleum and natural gas” to “petroleum” when referring to both.
[A] 0.0 to 2.5
[B] 2.5 to 5.0
[C] 5.0 to 7.5
[D] 7.5 to 10.0
Steel is an alloy made by combining iron and other elements, the most common of these being carbon. When carbon is used, its content in the steel is between 0.2% and 2. 1% by weight, depending on the grade. Other alloying elements sometimes used are manganese, chromium, vanadium and tungsten. Carbon and other elements act as a hardening agent, preventing dislocations in the iron atom crystal lattice from sliding past one another.
The German silver has long been in existence as it could be traced back to as far back as early 18th century. This Silver was developed in Germany by the German metalworkers in imitation of the Chinese alloys to be used as a substitute for silver since silver is highly expensive. The German silver is also known as the Nickel silver. These terms “German silver” and “Nickel silver” could be used interchangeably. It is a silver-white alloy of Copper, Zinc and Nickel. The German silver does not contain any trace of silver. The German silver is composed of three major elements Copper, Zinc and Nickel and sometimes with a trace of Tin and Lead. These elements vary in percentage with a range of Copper from approximately 50% – 61.6%, Zinc with an approximate range of 17.2& – 19% and Nickel with an approximate range of 21.1% – 30%. Theses compositions are always specified when it comes to commercial alloys. German silver is extensively used because of its hardness, toughness, and resistance to corrosion for articles such as tableware (commonly silver plated), marine fittings, and plumbing fixtures. Because of its high electrical resistance, it is used also in heating coils. It was discovered (early 19th cent.) by a German industrial chemist, E. A. Geitner.
Biogas is composed of Oxygen, Carbon dioxide, Nitrogen, Hydrogen, Methane and Hydrogen Sulphide compounds. Which one of the following compounds forms the majority?
[A] Carbon dioxide
[B] Carbon monoxide
[C] Hydrogen sulphide
Biogas or Gobar gas is produced by the anaerobic digestion or fermentation of biodegradable materials such as biomass, manure, sewage, municipal waste, green waste, plant material, and crops. It comprises primarily methane (CH4) and carbon dioxide (CO2) and may have small amounts of hydrogen sulphide (H2S), moisture and siloxanes. The composition of biogas varies depending upon the substrate composition, as well as the conditions within the anaerobic reactor (temperature, pH, and substrate concentration). Landfill gas typically has methane concentrations around 50%. Advanced waste treatment technologies can produce biogas with 55%–75% methane, which for reactors with free liquids can be increased to 80%–90% methane using in-situ gas purification techniques. As produced, biogas contains water vapour. The fractional volume of water vapour is a function of biogas temperature; correction of measured gas volume for water vapour content and thermal expansion is easily done via simple mathematics which yields the standardized volume of dry biogas.
[A] Formic acid
[B] Acetic acid
[C] Salicylic acid
[D] Oxalic acid
Vinegar is a liquid substance consisting mainly of acetic acid (CH3CO2H) and water, the acetic acid being produced through the fermentation of ethanol by acetic acid bacteria. It is today mainly used in the kitchen as a general cooking ingredient, but historically, as the most easily available mild acid, it had a great variety of industrial, medical, and domestic uses. Vinegar is a liquid that is produced from the fermentation of ethanol into acetic acid. The fermentation is carried out by bacteria. Vinegar consists of acetic acid (CH3COOH), water and trace amounts of other chemicals, which may include flavourings. The concentration of the acetic acid is variable. Distilled vinegar contains 5-8% acetic acid. Spirit of vinegar is a stronger form of vinegar that contains 5-20% acetic acid. Flavourings may include sweeteners, such as sugar or fruit juices. Infusions of herbs, spices and other flavours may be added, too. Vinegar is made from a variety of source materials. Each contributes its own unique flavour signature to the final product. Vinegar may be made from sugar cane juice, rice and other grains, grapes (balsamic vinegar), coconut water, fruit wines, kombucha, or apple cider. Spirit vinegar is a strong variety of vinegar (5% to 21% acetic acid) made from sugar cane and doubly fermented. The first fermentation changes sugar into alcohol, while the second fermentation changes alcohol into acetic acid.
Naphthalene is obtained from either coal tar or petroleum distillation. Naphthalene is derived from a kind of naphtha which is a broad term encompassing any volatile, namable liquid hydrocarbon mixture, including coal tar. It is also produced when things burn, so naphthalene is found in cigarette smoke, car exhaust, and smoke from forest fires. It is used as an insecticide and pest repellent. Naphthalene was first registered as a pesticide in the United States in 1948.
Vulcanization is a chemical process that converts natural rubber and other polydiene elastomers into cross-linked polymers. The most common vulcanization agent is sulfur. It forms bridges between individual polymer molecules when heated with rubber. Often a catalyst and initiator are added to accelerate the vulcanization process. The cross-linked elastomers have many improved mechanical properties. In fact, unvulcanized rubber has poor mechanical properties and is not very durable. In order to give more strength and more elasticity, natural rubber is heated with sulphur or sulphur compounds at 150°C temperature. Vulcanized rubber has good tensile strength.