Types of Chemical Reactions

Question: Who developed the ancient atomic theory?

Answer: The ancient atomic theory was proposed in the 5th century BC by the Greek philosophers Leucippus and Democritus. It was revived in the 1st century BC by the Roman philosopher and poet Lucretius. The modern atomic theory has undergone continuous refinement, began to flourish at the beginning of the 19th century with the work of the English chemist John Dalton.

Question: What chemical reaction produces wine and beer?

Answer: Fermentation is the chemical process by which molecules such as glucose breaks down anaerobically. More broadly, fermentation is the foaming that occurs during the manufacture of wine and beer, a process at least 10,000 years old. French chemist and microbiologist Louis Pasteur in the 19th century used the term fermentation in a narrow sense to describe the changes brought about by yeasts and other microorganisms growing in the absence of air (anaerobically).

Question: What acid''s formula is CH₃(CH₂)₇CH=CH(CH₂)₇CO₂HH?

Answer: Oleic acid, the most widely distributed of all the fatty acids, apparently occurring in all oils and fats. Oleic acid, CH₃(CH₂)₇CH=CH(CH₂)₇CO₂H, like other fatty acids, does not occur in the free state but is found as an ester of glycerol—i.e., as a glyceride or as an ester of long-chain alcohol.

Question: C₈H₈ is the chemical formula of which compound?

Answer: Styrene is a liquid hydrocarbon that is important chiefly for its marked tendency to undergo polymerization. Styrene is employed in the manufacture of polystyrene, an important plastic, and many specialty plastics and synthetic rubbers. The chemical formula for styrene is C₈H₈.

Question: What is the molecular formula of hematite?

Answer: Hematite, also spelled haematite, is a heavy and relatively hard oxide mineral, ferric oxide (Fe₂O₃), that constitutes the most important iron ore because of its high iron content (70 percent) and its abundance.

Question: Which formula represents the relative ratios of different atoms in a compound?

Answer: The various forms of Chemical formula are empirical, molecular, structural, and projection formulas. An empirical formula consists of symbols representing elements in a compound, such as Na for sodium and Cl for chlorine, and subscripts indicating the relative number of atoms of each constituent element. Empirical formulas are normally used to represent substances with undetermined molecular structures or substances not made up of normal molecular entities—e.g., sodium chloride (table salt), which is composed of ions.

Question: Who proposed the concept of acid and base based on the theory of ionization?

Answer: Swedish physicist and physical chemist Svante Arrhenius is known for his theory of electrolytic dissociation and his model of the greenhouse effect. In 1903 he was awarded the Nobel Prize for Chemistry. The Arrhenius theory, named after him, views an acid as a substance that increases the concentration of the hydronium ion (H₃O+) in an aqueous solution and a base as a substance that increases the hydroxide ion (OH−) concentration.

Question: 2Na + 2H₂O → 2NaOH + H₂

Answer: In a single displacement reaction, a single free element is substituted for one of the elements in a compound.

Question: In which reaction does a compound break down into simpler substances?

Answer: In Chemical reactions, decomposition reactions is a process in which chemical species break up into simpler parts. Usually, decomposition reactions require energy input. For example, a common method of producing oxygen gas in the laboratory is the decomposition of potassium chlorate (KClO₃) by heat.

Question: Which is the earliest sandwich compound?

Answer: Ferrocene, also called Dicyclopentadienyliron, is the earliest and best known of the so-called sandwich compounds. These are derivatives of transition metals in which two organic ring systems are bonded symmetrically to the metal atom. Its molecular formula is (C₅H₅)₂Fe.

Question: What reaction involves the absorption of energy to form new products?

Answer: Energy plays a vital role in chemical processes. According to the modern view of chemical reactions, bonds between atoms in the reactants must be broken, and the atoms or pieces of molecules are reassembled into products by forming new bonds. In some reactions, the energy required to break bonds is larger than the energy evolved on making new bonds, and the net result is the absorption of energy. Such a reaction is said to be endothermic if the energy is in the form of heat.

Question: HCl + NaOH → NaCl + H₂O

Answer: Double displacement reactions are basically an exchange of partners.

Question: A redox reaction is one in which...

Answer: Oxidation-reduction reaction, also called redox reaction is any chemical reaction in which the oxidation number of a participating chemical species changes.

Question: In which reaction is ozone employed to cleave the unsaturated compounds?

Answer: Ozonolysis or Harries reaction is a reaction used in organic chemistry to determine the carbon-carbon double bond in unsaturated compounds. It involves the reaction of the compound with ozone leading to the formation of an ozonide, and the ozonide yields on hydrogenation or treatment with an acid mixture containing aldehydes, ketones, or carboxylic acids.

Question: In which reaction does the treatment of amide with bromine and alkali give a primary amine?

Answer: Hofmann reaction is one of the prominent rearrangement reactions in which an amide is treated with chlorine or bromine and an aqueous alkali giving rise to an amine.

Question: What reaction takes place between molecular hydrogen and an element or compound in the presence of a catalyst?

Answer: Hydrogenation is a chemical reaction between molecular hydrogen and an element or compound, ordinarily in the presence of a catalyst. The reaction may be one in which hydrogen adds to a double or triple bond connecting two atoms in the structure of the molecule, or the addition of hydrogen results in dissociation (breaking up) of the molecule.

Question: What reaction of alkoxide ions with alkyl halides gives ether?

Answer: Ether is any of a class of organic compounds characterized by an oxygen atom bonded to two alkyl or aryl groups. The most versatile method for making ethers is the Williamson ether synthesis, named for English chemist Alexander Williamson, who devised the method in the 19th century. It uses an alkoxide ion to attack an alkyl halide, substituting the alkoxy (―O―R) group for the halide. The alkyl halide must be unhindered (usually primary), or elimination will compete with the desired substitution.

Question: What is the molecular formula of glucose?

Answer: Glucose, also called dextrose, is one of a group of carbohydrates known as simple sugars (monosaccharides). Glucose (from Greek “sweet”) has the molecular formula C₆H₁₂O₆. It is found in fruits and honey and is the free sugar circulating in the blood. It is the source of energy in cell function, and the regulation of its metabolism is of great importance.

Question: What chemical reaction causes rancidity in food?

Answer: Rancidity is a condition produced by aerial oxidation of unsaturated fat present in foods and other products, leading to unpleasant odor or flavor. Exposure of a fatty substance to air converts unsaturated components into hydroperoxides, which break down into volatile aldehydes, esters, alcohols, ketones, and hydrocarbons, some of which have disagreeable odors.

Question: What is the ratio of reactants and products in a chemical reaction called?

Answer: In Chemistry, stoichiometry is the determination of the proportions in which elements or compounds react with one another. The rules followed in the determination of stoichiometric relationships are based on the laws of conservation of mass and energy and the law of combining weights or volumes

Question: Name the substance that causes a foaming action in doughs and batters.

Answer: A leavening agent is a substance causing expansion of doughs and batters by the release of gases within such mixtures. Such agents include air, steam, yeast, baking powder, and baking soda. Leavening of baked foods with air is achieved by vigorous mixing that incorporates air bubbles, producing foam.

Question: Which chemical process combines light, gaseous hydrocarbons to produce high-octane components of gasoline?

Answer: Alkylation is a chemical process in which light, gaseous hydrocarbons are combined to produce high-octane gasoline components. The light hydrocarbons consist of olefins such as propylene and butylene, and isoparaffins. These compounds are fed into a reactor, where, under the influence of a sulfuric-acid or hydrofluoric-acid catalyst, they combine to form a mixture of heavier hydrocarbons. The liquid fraction of this mixture, known as alkylate, consists mainly of isooctane, a compound that lends excellent antiknock characteristics to gasolines.

Question: What type of chemical reaction happens in burning a matchstick?

Answer: An example of a combustion reaction is a lighted match. When a match is struck, friction heats the head to a temperature at which the chemicals react and generate more heat than can escape into the air, and they burn with a flame. If a wind blows away the heat or the chemicals are moist, and friction does not raise the temperature sufficiently, the match goes out. Properly ignited, the heat from the flame raises the temperature of a nearby layer of the matchstick and oxygen in the air adjacent to it, and the wood and oxygen react in a combustion reaction.

Question: What chemical reaction causes corrosion of iron?

Answer: Corrosion is wearing away due to chemical reactions, mainly oxidation (see oxidation-reduction, oxide). It occurs whenever a gas or liquid chemically attacks an exposed surface, often a metal, and is accelerated by warm temperatures and by acids and salts. Normally, corrosion products (e.g., rust, patina) stay on the surface and protect it.

Question: Name the hydrocarbon that contains at least one carbon-to-carbon double bond?

Answer: Olefin, also called alkene, is a compound made up of hydrogen and carbon that contains one or more pairs of carbon atoms linked by a double bond. Olefins are examples of unsaturated hydrocarbons.

Question: What is the final product of nitration of toluene?

Answer: Trinitrotoluene (TNT) is a pale yellow, solid organic nitrogen compound used chiefly as an explosive, prepared by stepwise nitration of toluene. Because TNT melts at 82° C (178° F) and does not explode below 240° C (464° F), it can be melted in steam-heated vessels and poured into casings. It is relatively insensitive to shock and cannot be exploded without a detonator. For these reasons, it is the most favored chemical explosive, extensively used in munitions and for demolitions.

Question: What chemical is formed when water reacts with sulfur trioxide?

Answer: Sulfuric acid is a dense, colorless, oily, corrosive liquid and one of the most commercially important chemicals. Sulfuric acid is prepared industrially by the reaction of water with sulfur trioxide. Sulfuric acid is used in the manufacture of fertilizers, pigments, dyes, drugs, explosives, detergents, and inorganic salts and acids, as well as in petroleum refining and metallurgical processes.

Question: What law states that a compound is always composed of the same elements by mass?

Answer: The law of definite proportions states that every chemical compound contains fixed and constant proportions (by mass) of its constituent elements. Although many experimenters had long assumed the truth of the principle in general, the French chemist Joseph-Louis Proust first accumulated conclusive evidence for it in a series of researches on the composition of many substances, especially the oxides of iron (1797).

Question: What reaction is formed when benzaldehyde is treated with a concentrated base?

Answer: In 1853, Italian chemist Stanislao Cannizzaro discovered that when benzaldehyde is treated with a concentrated base, both benzoic acid and benzyl alcohol are produced—a phenomenon known today as the Cannizzaro reaction.

Question: Which of the following is known as slaked lime?

Answer: Calcium hydroxide, also called slaked lime, Ca(OH)2, is obtained by the action of water on calcium oxide. When mixed with water, a small proportion of it dissolves, forming a solution called limewater, the rest remaining as a suspension called milk of lime. Calcium hydroxide is used as an industrial alkali and as a constituent of mortars, plasters, and cement. It is used in the kraft paper process and as a flocculant in sewage treatment.

Question: In which process does a substance absorb moisture from the atmosphere?

Answer: Deliquescence is the process by which a substance absorbs moisture from the atmosphere until it dissolves in the absorbed water and forms a solution. Deliquescence occurs when the vapor pressure of the solution formed is less than the partial pressure of water vapor in the air. A substance that absorbs moisture from the air but not necessarily to the point of dissolution is called hygroscopic.

Question: Which compound is represented by the generic formula RMgX?

Answer: Grignard reagent is any of numerous organic derivatives of magnesium (Mg) commonly represented by the general formula RMgX (in which R is a hydrocarbon radical: CH₃, C₂H₅, C₆H₅, etc. and X is a halogen atom, usually chlorine, bromine, or iodine). They are called Grignard reagents after their discoverer, French chemist Victor Grignard, who was a co-recipient of the 1912 Nobel Prize for Chemistry for this work.

Question: With whom did Victor Grignard win the Nobel Prize for Chemistry in 1912 for discovering the use of nickel as a catalyst in hydrogenation?

Answer: French organic chemist Paul Sabatier was the co-recipient of the 1912 Nobel Prize for Chemistry with Victor Grignard, for Chemistry for researches in catalytic organic synthesis, in particular for discovering the use of nickel as a catalyst in hydrogenation (the addition of hydrogen to molecules of carbon compounds).

Question: Which compound is generated in certain foods as a result of cooking at high temperatures?

Answer: acrylamide, also called 2-propenamide, ethylene carboxamide, or acrylic amide, is a white, odorless, crystalline substance belonging to the family of organic compounds, and its molecular formula is C₃H₅NO. Acrylamide is produced as a result of industrial processes and is generated in certain foods, hence cooking at high temperatures.

Question: What is the molecular formula of ethanol?

Answer: Ethanol, also called ethyl alcohol, grain alcohol, or alcohol, is a member of a class of organic compounds that are given the general name alcohols. Its molecular formula is C₂H₅OH. Ethanol is an important industrial chemical. It is used as a solvent, in the synthesis of other organic chemicals, and as an additive to automotive gasoline. Ethanol is also the intoxicating ingredient in many alcoholic beverages such as beer, wine, and distilled spirits.

Question: What is the other name for quick lime?

Answer: Calcium is the most abundant metallic element in the human body and the fifth most abundant element in Earth’s crust. One calcium compound, calcium oxide (CaO), also known as lime, or more specifically, quicklime, was extensively used by the ancients. Calcium oxide is a white or grayish-white solid produced in large quantities by roasting calcium carbonate to drive off carbon dioxide. At room temperature, CaO will spontaneously absorb carbon dioxide from the atmosphere, reversing the reaction.

Question: Pb₁SO₄ is the chemical formula of which of the following elements?

Answer: Anglesite is a naturally occurring lead sulfate (PbSO₄), a common secondary mineral that is a minor ore of lead. It is usually formed by the oxidation of galena and often make a concentrically banded mass surrounding a core of unaltered galena. The formation of cerussite often accompanies or follows the forming of anglesite.

Question: S + O₂ →  SO₂

Answer: In synthesis reactions, two or more reactants combine to form a single product.

Question: Name the product formed by the ammoxidation of propene and ammonia?

Answer: Nitrile is any of a class of organic compounds having molecular structures in which a cyano group (―C ≡ N) is attached to a carbon atom (C). Acrylonitrile is produced in large quantities by a process called ammoxidation that depends on the oxidation of propylene in the presence of ammonia and a catalyst. Acrylonitrile constitutes a major component of several polymeric substances, including acrylic textile fibers and synthetic rubbers, and thermoplastic resins.

Question: What is the ratio of the volume of hydrogen and oxygen present in water?

Answer: The water molecule is composed of two hydrogen atoms, each linked by a single chemical bond to an oxygen atom. Most hydrogen atoms have a nucleus consisting solely of a proton. Two isotopic forms, deuterium and tritium, in which the atomic nuclei also contain one and two neutrons, respectively, are found to a small degree in water.

Question: 2Na + Cl₂ → 2NaCl

Answer: Synthesis reactions are those in which two or more reactants unite to produce a single product.

Question: What is the common name of sodium carbonate decahydrate?

Answer: Washing soda, also known as sal soda, or sodium carbonate decahydrate is an efflorescent crystals used for washing, especially textiles. It is a compund of sodium and its molecular formula is Na₂CO₃.

Question: CaCO₃ → CaO + CO₂

Answer: In chemistry, decomposition is the breaking down of a single reactant into two or more products.

Question: What is the branch of chemistry which deals with the study of chemical reaction rate?

Answer: Chemical kinetics is the branch of physical chemistry that is concerned with understanding the rates of chemical reactions. It is to be contrasted with thermodynamics, which deals with the direction in which a process occurs but in itself tells nothing about its rate. The principles of chemical kinetics apply to purely physical processes as well as to chemical reactions.

Question: Which chemical reaction is caused by the absorption of light energy?

Answer: Photochemical reaction is a chemical reaction initiated by the absorption of energy in the form of light. The consequence of molecules’ absorbing light is the cause of transient excited states whose chemical and physical properties differ greatly from the original molecules.

Question: In which reaction does water act as a reactant?

Answer: In chemistry and physiology, Hydrolysis is a double decomposition reaction with water as one of the reactants. Thus, if a compound is represented by the formula AB in which A and B are atoms or groups and water is represented by the formula HOH, the hydrolysis reaction may be represented by the reversible chemical equation AB + HOH ⇌ AH + BOH.

Question: What substance causes a chemical reaction without itself being affected?

Answer: Catalyst is any substance that increases the rate of a reaction without being consumed. Enzymes are naturally occurring catalysts responsible for many essential biochemical reactions.

Question: Which reaction involves the halogenation of carboxylic acids at the alpha (α) carbon?

Answer: Carboxylic acid can be halogenated at the alpha carbon by treatment with a halogen and a catalyst, usually phosphorus trichloride. This reaction, called the Hell-Volhard-Zelinskii reaction, actually takes place on the acyl halide rather than on the acid itself. The purpose of the catalyst is to convert some of the acid molecules to the acyl halide, which is the compound that actually undergoes the α-halogenation.

Question: What is the reaction that adds monomer molecules together to form chains?

Answer: Polymerization is any process in which relatively small molecules, called monomers, combine chemically to produce a large chainlike or network molecule, called a polymer. The monomer molecules may be all alike, or they may represent two, three, or more different compounds.

Question: Zn + 2HCl → H₂ + ZnCl₂

Answer: Also known as substitution or single replacement, a single displacement reaction consists of a single element replacing one of the elements in a compound.

Question: What is the conversion of butane to isobutane called?

Answer: Isomerization is the chemical process by which a compound is transformed into any of its isomeric forms, i.e., it forms with the same chemical composition but with a different structure or configuration and with different physical and chemical properties. An example is the conversion of butane, a hydrocarbon with four carbon atoms joined in a straight chain, to its branched-chain isomer, isobutane, by heating the butane to 100° C or higher in the presence of a catalyst.

Question: CaCO₃ + 2HCl → CaCl₂ + H₂CO₃

Answer: In the double displacement of ionic compounds, the positive and negative ions of each reactant are flipped in the products.

Question: How many types of substitution reactions are there?

Answer: Substitution reaction is any of a class of chemical reactions in which an atom, ion, or group of atoms or ions in a molecule is replaced by another atom, ion, or group. Substitution reactions are divided into three classes, depending on the type of atom or group that acts as the substituent- Nucleophilic substitution, Electrophilic substitution, and Radical reagents.

Question: What chemical reaction is involved in the production of soap?

Answer: The early soap making process probably used ashes and animal fats. This mixture was then boiled, ashes added again and again as the water evaporates. During this process, a slow chemical splitting of the neutral fat takes place. The fatty acids could then react with the alkali carbonates of the plant ash to form soap. This reaction is called saponification.

Question: What chemical reaction uses direct electric current to drive chemical reaction?

Answer: Electrolysis is a process by which electric current is passed through a substance to effect a chemical change. The chemical change is one in which the substance loses or gains an electron (oxidation or reduction). The process is carried out in an electrolytic cell, an apparatus consisting of positive and negative electrodes held apart and dipped into a solution containing positively and negatively charged ions.

Question: Who coined the term "ester"?

Answer: Ester is any of a class of organic compounds that react with water to produce alcohols and organic or inorganic acids. Esters derived from carboxylic acids are the most common. The term ester was introduced in the first half of the 19th century by German chemist Leopold Gmelin.

Question: 2H₂O → 2H₂ + O₂

Answer: In decomposition reactions, a single reactant is broken down into two or more products.

Question: Who introduced the proton theory of acids and bases?

Answer: The Brønsted–Lowry theory, also called proton theory of acids and bases, was introduced independently in 1923 by the Danish chemist Johannes Nicolaus Brønsted and the English chemist Thomas Martin Lowry. It states that any compound that can transfer a proton to any other compound is an acid, and the compound that accepts the proton is a base.