Test: SSC CGL Previous Year Questions: Chemistry (2023-20) - 2 - SSC CGL MCQ

Eicosane (C₂₀H₄₂) - It is a very hydrophobic molecule, practically insoluble in water, and relatively neutral. It is considered to be a hydrocarbon lipid molecule.

Butyric acid (C₄H₈O₂). Propionic Acid (C₃H₆O₂) - A colourless liquid with a sharp rancid odour. It is a short-chain saturated fatty acid comprising ethane attached to the carbon of a carboxy group. Succinic Acid (C₄H₆O₄) - An alpha,omega-dicarboxylic acid resulting from the formal oxidation of each of the terminal methyl groups of butane to the corresponding carboxy group. Lactic Acid (C₃H₆O₃) - A colourless to yellow odourless syrupy liquid, Used to make cultured dairy products, as a food preservative.

Anthracene (C₁₄H₁₀). It is a colourless crystalline aromatic hydrocarbon, and a three-fused benzene ring solid polycyclic aromatic hydrocarbon (PAH). It is a component of coal tar. Anthracene is used in the production of the red dye alizarin and other dyes.

Lactose (Milk sugar). It is a disaccharide which is made by the condensation of glucose and galactose. Examples : Butter, Cheese, Cream, Dried milk, Milk solids, Powdered milk, and Whey.

Aniline (C₆H₅NH₂). A class of organic molecules known as Phenylamine Aminobenzene Benzamine.

Phthalaldehyde {C₆H₄(CHO)₂} : Uses - for the detection of biogenic amines, peptides, proteins in nanogram quantities in body fluids.

Double Bond. Alkene (C_nH_2n). Example - Ethene (C₂H₄), Propene (C₃H₆), Butene (C₄H₈). Alkyne (C_nH_2n-2) - Hydrocarbon consists of carbon bound to a carbon with a triple bond, and each carbon is then attached to zero or one hydrogen atom. Example - Ethyne (C₂H₂), Propyne (C₃H₄). Alkanes (C_nH_2n+2) - Contains strong carbon-carbon single bonds and strong carbon-hydrogen bonds. Example - Methane (CH₄), Ethane (C₂H₆) .

Ethynyl. An organic radical and a terminal acetylenic compound. Uses: Fuel, Industrial applications, Medical applications.

Chloroform (CHCl₃) - It is used as an ideal anaesthetic. It is a colourless, sweet-smelling dense liquid. Other names - Formyl Trichloride, TriChloroform.

Alcohol. Functional Group, Formula, Sux and Example : (Alcohol, R-OH, -ol, Methanol), (Ketone, R-(CO)-R’, -one, Butanone), (Aldehyde, R-CHO, -al, Ethanal), (Acyl Halide, R-(CO)-X, -oyl halide, Ethanoyl Chloride), Carboxylate, R-COO– , -oate, Sodium Ethanoate), (Carboxylic Acid, R-COOH, -oic acid, Ethanoic Acid), (Ester, R-(CO)-O-R’, Alkyl alkanoate, Ethyl Butanoate), (Ether, R-O-R’, Alkyl ether, Diethyl Ether).

CH₃NO₂ . Nitromethane is used to make industrial antimicrobials and pharmaceuticals, and is also used as a soil fumigant and as a fuel in race car engines.

Alkanes are a series of compounds that contain carbon and hydrogen atoms with single covalent bonds.

Ester is a chemical compound derived from an acid in which at least one –OH hydroxyl group is replaced by an –O– alkyl group, as in the substitution reaction of a carboxylic acid and an alcohol. Example- Ethyl acetate, propyl methanoate, etc. The term ester was introduced by German chemist Leopold Gmelin.

International Union of Pure and Applied Chemistry (IUPAC). Suffix - A functional group belonging to the molecule which follows the root of the name. Prefixes - They indicate the presence of side chains or substituent groups in the given organic molecule.

C-12. Atomic mass is dened as mass equal to one twelfth of the mass of a Carbon atom. The mass of any isotope of any element is expressed in relation to the Carbon-12 standard.

Pyruvate is generated through glycolysis. Glycolysis begins with the six-carbon monosaccharide - glucose. In the rst few steps, glucose undergoes phosphorylation and isomerization to produce fructose -6-phosphate. Another phosphorylation reaction facilitates the splitting of this hexose sugar into two 3-carbon molecules - glyceraldehyde phosphate (G3P) and dihydroxyacetone phosphate (DHAP).

Diagonal relationship. Magnesium and Lithium are almost of the same sizes and electronegativity values are nearly the same because both are found together in nature. A Diagonal Relationship is said to exist between certain pairs of diagonally adjacent elements in the second and third periods of the periodic table. These pairs (Li & Mg, Be & Al, B & Si, etc.) exhibit similar properties.

Z. Moseley rearranged the elements in the periodic table on the basis of atomic numbers. Examples: Oxygen (¹⁶O₈) - Atomic number (Z) - 8 and atomic mass(A) - 16.

Be < Mg < Ca < Sr < Ba. Alkaline earth metals : Second most reactive family of elements, present in group 2 of the modern periodic table. Elements and their atomic number : Alkaline earth metals - Beryllium (4), Magnesium (12), Calcium (20), Strontium (38), Barium (56). Halogen (Group 17 or Group VIIA) - Fluorine (9), Chlorine (17), Bromine (35), Iodine (53). Oxygen family (Group 16 or Group VIA) - Oxygen (8), Sulphur (16), Selenium (34).

Nitrogen (N). Other elements with their atomic number: Silicon (Si, 14), Phosphorus(P, 15), Sulphur(S,16), Argon (Ar, 18), Potassium (K, 19), Scandium(Sc, 21), Titanium (Ti, 22), Calcium (Ca, 20), Chlorine (Cl, 17), Oxygen (O, 8).

Lothar Meyer. William Ramsay - British physical chemist who discovered four gases (neon, argon, krypton, xenon) and showed that they (with helium and radon) formed an entire family of new elements, the noble gases. Award: Nobel Prize (1904). John Newlands: “Law of octaves “ When elements are arranged in increasing order of their atomic masses, every eighth element has the same properties as the rst element. Glenn T Seaborg: His work on isolating and identifying transuranium elements (those heavier than uranium).

There are six groups of p–block elements in the periodic table numbering from 13 to 18. Boron, carbon, nitrogen, oxygen, uorine and helium head the groups. Their valence shell electronic conguration is ns2 np1-6 (except for He). The maximum oxidation state shown by a p-block element is equal to the total number of valence electrons. In the P block of periodic table the non-metallic character of elements decreases down the group. In fact the heaviest element in each p-block group is the most metallic in nature.

Gallium. Group 13 Elements: The Boron Family - Boron is a typical non-metal. Aluminium is a metal but shows many chemical similarities to boron, and gallium, indium and thallium are almost exclusively metallic in character. Boron is a fairly rare element, mainly occurs as orthoboric acid (H₃BO₃), borax (Na₂B₄O₇ ·₁₀H₂O) and kernite (Na₂B₄O₇·₄H₂O). There are two isotopic forms of boron 10B (19%) and 11B (81%).

Sodium. Alkali metals: Lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr) are soft, shiny, low-melting, highly reactive metals which tarnish quickly when exposed to air due to reaction with Oxygen, moisture oxides, hydroxides, and CO₂ present in air to form carbonates.

1865. Law of Octaves - Every eighth element has similar properties when the elements are arranged in the increasing order of their atomic masses.

Beryllium (Be, 4). Mixing it with metals increases their electrical and thermal conductivity

Hydrogen (H). Alkali metals - They form hydroxides on reaction with water which are strongly alkaline in nature. Physical Properties of Alkali metals - Silvery white, soft, light, malleability, high thermal and electrical conductivity.