A quick 25 questions article on Chemistry – General Knowledge – MCQs important for competitive exams like in UPSC, state civil services, olympiads etc.
Que (1): Which acid is used to remove ink and rust stains from cloth?
A. Hydrolic oxide
B. Oxalic acid
C. Citric Acid
D. none of these
Answer: Oxalic acid
Explanation: Oxalic acid is widely used as an acid rinse in laundries, where it is effective in removing rust and ink stains because it converts most insoluble iron compounds into a soluble complex ion
Que (2): Which are the metal that is present in photo films?
Explanation: The metal that is present in photo films is silver. The light-sensitive chemicals used in photographic film and paper are silver halides. Silver halide crystals in gelatin are coated on to a film base, glass or paper substrate
Que (3): Which is the highest grade of coal whose surface is shining and has the highest calorific value?
D. all of these
Explanation: The highest grade of coal whose surface is shining and has the highest calorific value, is Anthracite. Anthracite, often referred to as hard coal, is a hard, compact variety of coal that has a submetallic luster.
Que (4): Which elements is most abundant in the earth’s crust?
Explanation: The Most Abundant Elements In The Earth’s Crust. Oxygen, silicon, and aluminium are the three most common elements in the Earth’s crust.
Que (5): Which is an element which never exhibits positive oxidation state in any of its compounds?
Explanation: An element that never has a positive oxidation state in any of its compound is fluorine. Fluorine only shows negative oxidation states whereas other halogens shows negative as well as positive oxidation state.
Que (6): In which situation a chemical reaction does not occur?
A. Common salt is exposed to air
B. Common salt is not exposed to air
C. If it is not kept under proper temperature
D. No catalyst
Answer: Common salt is exposed to air
Explanation: Salt, the most commonly known of which is sodium chloride, or table salt, is a compound formed by the chemical reaction of an acid with a base.
Que (7): Blue litmus paper is converted into red in solution of which thing?
Explanation: Blue litmus paper turns red under acidic conditions and red litmus paper turns blue under basic or alkaline conditions, with the color change occurring over the pH range
Que (8): Which is another name of RDX ?
B. Beta Polymorphs
Explanation: RDX is also known, but less commonly, as cyclonite, hexogen (particularly in Russian, French, German and German-influenced languages), T4, and, chemically, as cyclotrimethylenetrinitramine.
Que (9): What is the negative logarithmic value of hydrogen is called?
D. None of these
Explanation: The logarithm of the hydrogen ion concentration in a solution, with the sign changed from positive to negative, is called the pH.
Que (10): A bee-sting leaves an acid which causes pain and irritation. which is that injected acid?
A. Formic acid
B. Carminic Acid
C. Acetic Acid
D. Methanoic acid
Answer: Formic acid
Explanation: Formic Acid is a reagent comprised of the organic chemical formic acid that cleaves proteins into peptides at the C- or N-terminal side of an aspartate residue.
Que (11): By which method a mixture of naphthalene and benzoic acid can be separated?
Explanation: Chromatography is a laboratory technique for the separation of a mixture. The mixture is dissolved in a fluid called the mobile phase, which carries it through a structure holding another material called the stationary phase.
Que (12): By which Carbon and hydrogen are estimated in organic compounds?
A. Stock estimation method
B. Allometric method
D. Liebig’s method
Answer: Liebig’s method
Explanation: Liebig’s method is used for the estimation of “Carbon and hydrogen”. Principle: A known mass of organic compound is heated in the presence of pure oxygen. The carbon dioxide and water formed are collected and weighed.
Que (13): Radioactive disintegration of uranium ultimately results in which formation?
Explanation: Some isotopes will only need to go through a few decay steps to become stable, while others will go through many radioactive decay steps to become stable.
Que (14): Which isotope of uranium capable of sustaining chain reactions?
Explanation: A fissionable material, such as uranium-235, is a material capable of producing enough free neutrons to sustain a nuclear chain reaction. Only 0.7204% of naturally occurring uranium is uranium-235.
Que (15): Which is natural source of gamma-rays?
A. Helium gas
B. Freon gas
D. Radon gas
Answer: Radon gas
Explanation: They are produced by the hottest and most energetic objects in the universe, such as neutron stars and pulsars, supernova explosions, and regions around black holes.
Que (16): Which is the sweetest sugar?
Explanation: Fructose is the sweetest sugar amongst all the given sugars. An estimation of concentration of sugar revealed that if sucrose has a sweetness of one, glucose will be 0.74 and fructose may count up to 1.7.
Que (17): Which is the substance which can act both as an acid and a base?
Explanation: An amphoteric substance is a substance that can act as both acids and base by being both proton acceptor and proton donor. Thus the bicarbonate ion HCO3− is an amphoteric substance.
Que (18): Which was the gas which had leaked out of Union Carbide factory in Bhopal?
A. Ethyl isocynate
B. Methyl isocynate
C. Propyl isocynate
D. Butyl isocynate
Answer: Methyl isocynate
Explanation: It happened at a Union Carbide subsidiary pesticide plant in the city of Bhopal, India. On the night of 2-3 December 1984, the plant released approximately 40 tonnes of toxic methyl isocyanate (MIC) gas, exposing more than 500,000 people to toxic gases.
Que (19): Which property of the elements is a whole number?
A. Atomic weight
B. Atomic number
C. Atomic property
D. Atomic mass
Answer: Atomic number
Que (20): What are the atoms of the elements which have same number of neutrons called?
D. none of these
Explanation: Isotone, any of two or more species of atoms or nuclei that have the same number of neutrons.
Que (21): What is the most abundant on the earth crust?
Explanation: Oxygen is the most abundant element in the Earth’s crust, and accounts for about 46%. Silicone is the next most abundant element at 27.7%, while aluminium accounts for 8.1%.
Que (22): Which metal is extracted by electrolytic reaction method?
Explanation: Aluminium is extracted by electrolytic reduction method. In electro-refining method, impure metal is taken as anode and pure metal is made of cathode. The electrodes are placed in acidified aqueous solution of metal salt or molten metal salt.
Que (23): Which is the basis of modern periodic table?
A. Atomic Number
B. Atomic Mass
C. Atomic weight
D. none of these
Answer: Atomic number
Explanation: The modern periodic table is developed after the periodic law and a periodic table given by Mendeleev.
Que (24): By which can the location and energy of an electron in an atom be specified?
B. Whole numbers
C. Real numbers
D. Quantum numbers
Answer: Quantum numbers
Explanation: Generally speaking, the energy of an electron in an atom is greater for greater values of n. This number, n, is referred to as the principle quantum number. The principle quantum number defines the location of the energy level.
Que (25): Which is also called Stranger Gas?
Explanation: Xenon (Xe, Element 54) Xenon, from the Greek for ‘stranger’ is a colourless, odourless group 18 noble gas.
Other relevant links:
- Chemistry Objective GK Mock Test – 1
- Chemistry Objective GK Mock Test – 2
- Chemistry Objective GK Mock Test – 3
Hope this article has provided you with some relevant knowledge for your exams. Do let us know in comments if this article is of help or if you want us to cover some other topic.