MCQOPTIONS
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MCQOPTIONS
This section includes 351 Mcqs, each offering curated multiple-choice questions to sharpen your UPSC IAS Exam knowledge and support exam preparation. Choose a topic below to get started.
| 251. |
Which of the following is a good lubricant? [CDS] |
| A. | Diamond powder |
| B. | Graphite powder |
| C. | Molten carbon |
| D. | Alloy of carbon and iron |
| Answer» C. Molten carbon | |
| 252. |
To weld metals together, high temperature is required. Such a high temperature is obtained by burning [NDA] |
| A. | Acetylene in oxygen |
| B. | LPG in oxygen |
| C. | Methane in oxygen |
| D. | Acetylene in nitrogen |
| Answer» B. LPG in oxygen | |
| 253. |
The main constituent of vinegar is |
| A. | Acetic acid |
| B. | Ascorbic acid |
| C. | Citric acid |
| D. | Tartaric acid |
| Answer» B. Ascorbic acid | |
| 254. |
Which one among the following transitions of electron of hydrogen atom emits radiation of the shortest wavelength? [NDA] |
| A. | n = 2 to n = 1 |
| B. | n = 3 to n = 2 |
| C. | n = 4 to n = 3 |
| D. | n = 5 to n = 4 |
| Answer» B. n = 3 to n = 2 | |
| 255. |
Match List I with List II and select the correct answer using the code given below the Lists : [NDA] List I (Scientist) List II (Discovery)A.Goldstein1.Atomic theoryB.Chadwick2.ProtonC. J.J Thomson3.NeutronD. John Dalton4.Electron |
| A. | A-2, B-3, C-4, D-1 |
| B. | A-2, B-4, C-3, D-1 |
| C. | A-1, B-4, C-3, D-2 |
| D. | A-1, B-3, C-4, D-2 |
| Answer» B. A-2, B-4, C-3, D-1 | |
| 256. |
Why bases are kept in glass bottles? |
| A. | Bases produce \[O{{H}^{-}}\] ions in aqueous solutions |
| B. | Basic solutions are conducting in nature |
| C. | Bases are corrosive in nature |
| D. | Bases have soapy texture |
| Answer» D. Bases have soapy texture | |
| 257. |
Bleaching powder gives smell of chlorine because it- |
| A. | is unstable |
| B. | gives chlorine on exposure to atmosphere |
| C. | is a mixture of chlorine and slaked lime |
| D. | contains excess of chlorine |
| Answer» C. is a mixture of chlorine and slaked lime | |
| 258. |
Iron sheet kept in moist air covered with rust. Rust is [CDS] |
| A. | an element |
| B. | a compound |
| C. | a mixture of iron and dust |
| D. | a mixture of iron, oxygen and water |
| Answer» C. a mixture of iron and dust | |
| 259. |
What type of mixture is smoke? [CDS] |
| A. | Solid mixed with a gas |
| B. | Gas mixed with a gas |
| C. | Liquid mixed with a gas |
| D. | Gas mixed with a liquid and a solid |
| Answer» E. | |
| 260. |
The chemical formula of Borax is |
| A. | \[N{{a}_{2}}{{B}_{4}}{{O}_{7}}\] |
| B. | \[CaCOC{{I}_{2}}\] |
| C. | \[BaS{{O}_{4}}\] |
| D. | \[Ca{{(S{{O}_{4}})}_{2}}\] |
| Answer» B. \[CaCOC{{I}_{2}}\] | |
| 261. |
Wooden pencil used for writing contains |
| A. | Graphite |
| B. | Lead |
| C. | Salt |
| D. | Cane sugar |
| Answer» B. Lead | |
| 262. |
The chemical formula of plaster of parts is [BPSC] |
| A. | \[CaS{{O}_{4}}.5{{H}_{2}}O\] |
| B. | \[2CaS{{O}_{4}}.{{H}_{2}}O\] |
| C. | \[(CaS{{O}_{4}}).2{{H}_{2}}O\] |
| D. | \[COSO4.MGO\] |
| Answer» D. \[COSO4.MGO\] | |
| 263. |
Column-I Column-II A. Hardest Non-metal P. Graphite B. Non-metal conducts electricity Q. Sulphur C. Non-metal with lustre R. Diamond (Carbon) D. Non-metal used as fungicide S. Iodine |
| A. | A-R; B-P; C-S; D-Q |
| B. | A-Q; B-P; C-S; D-R |
| C. | A-P; B-R; C-S; D-Q |
| D. | A-R; B-P; C-Q; D-S |
| Answer» B. A-Q; B-P; C-S; D-R | |
| 264. |
Which method is employed for obtaining a pure metal? |
| A. | Froth floatation |
| B. | Electrolytic refining |
| C. | Magnetic separation |
| D. | Gravity separation |
| Answer» C. Magnetic separation | |
| 265. |
Which one of the following is used in the preparation of antiseptic solution? [CDS] |
| A. | Potassium nitrate |
| B. | Iodine |
| C. | Iodine chloride |
| D. | Potassium chloride |
| Answer» C. Iodine chloride | |
| 266. |
Aqua-regia used by alchemists to separate silver and gold is a mixture of [CDS] |
| A. | hydrochloric acid (concentrated) and nitric acid (concentrated) |
| B. | hydrochloric acid (concentrated) and sulphuric acid (concentrated) |
| C. | nitric acid (concentrated) and sulphuric acid (concentrated) |
| D. | hydrochloric acid (dilute) and sulphuric acid (dilute) |
| Answer» B. hydrochloric acid (concentrated) and sulphuric acid (concentrated) | |
| 267. |
1 u or 1 amu means |
| A. | 1/12th mass of C-12 atoms |
| B. | Mass of C-12 atom |
| C. | Mass of O-16 atom |
| D. | Mass of Hydrogen molecule |
| Answer» B. Mass of C-12 atom | |
| 268. |
Which is the symbol of the element tungsten? [NDA] |
| A. | Ta |
| B. | Tc |
| C. | W |
| D. | V |
| Answer» D. V | |
| 269. |
Which one of the following is heavy water used in nuclear reactor? [CDS] |
| A. | Water having molecular weight 18 u |
| B. | Water having molecular weight 20 u |
| C. | Water at \[4{}^\circ C\] but having molecular weight 19u |
| D. | Water below the ice in a frozen sea |
| Answer» C. Water at \[4{}^\circ C\] but having molecular weight 19u | |
| 270. |
Which one of the following is not needed in a nuclear fission reactor? [CDS] |
| A. | Moderator |
| B. | Coolant |
| C. | Accelerator |
| D. | Control device |
| Answer» D. Control device | |
| 271. |
Which one of the following is correct? Butter is [CDS] |
| A. | a super cooled oil |
| B. | an emulsion |
| C. | a molecular solid |
| D. | None of these |
| Answer» E. | |
| 272. |
Amalgam is a solution of |
| A. | solid in solid |
| B. | solid in liquid |
| C. | liquid in solid |
| D. | liquid in liquid |
| Answer» D. liquid in liquid | |
| 273. |
Bases turn red litmus blue and acids turn blue litmus red. A student tested a liquid with a red litmus paper and it stayed red with no change. This shows that the liquid [NDA] |
| A. | must be pure water |
| B. | must be an acid |
| C. | is not a base |
| D. | is neither a base nor an acid |
| Answer» B. must be an acid | |
| 274. |
Which of the following statements regarding oxidation and reduction are correct? [NDA] 1. In oxidation, loss of electron takes place whereas in reduction, gain of electron takes place. 2. In oxidation, gain of electron takes place whereas in reduction, loss of electron takes place. 3. Oxidizing agent decreases the oxidation number but reducing agent increases the oxidation number. 4. Oxidizing agent increases the oxidation number but reducing agent reduces the oxidation number. Select the correct answer using the code given below: Code: |
| A. | 1 and 3 |
| B. | 2 and 4 |
| C. | 2 and 3 |
| D. | 1 and 4 |
| Answer» E. | |
| 275. |
Which one of the following reactions is the main cause of the energy radiation from the Sun? [CDS] |
| A. | Fusion reaction |
| B. | Fission reaction |
| C. | Chemical reaction |
| D. | Diffusion reaction |
| Answer» B. Fission reaction | |
| 276. |
Age of fossil may be found out by determining the ratio of two isotopes of carbon. The isotopes are [CDS] |
| A. | C-12 and C-13 |
| B. | C-13 and C-14 |
| C. | C-12 and C-14 |
| D. | C-12 and carbon black |
| Answer» D. C-12 and carbon black | |
| 277. |
Heavy water implies [CDS] |
| A. | water which is used in heavy industries such as thermal power plants |
| B. | water which contains \[S{{O}_{4}}^{2-}\] and \[C{{I}^{-}}\] of calcium and magnesium |
| C. | deuterated water |
| D. | water which has maximum density |
| Answer» D. water which has maximum density | |
| 278. |
A gas can be compressed to a fraction of its volume. The same volume of a gas can be spread all over a room. The reason for this is that |
| A. | the volume occupied by molecules of a gas is negligible as compared to the total volume of the gas. |
| B. | gases consists of molecules which are in a state of random motion |
| C. | gases consist of molecules having very large inter-molecular space which can be reduced or increased under ordinary conditions |
| D. | None of these |
| Answer» D. None of these | |
| 279. |
What happens when a fixed amount of oxygen gas is taken in a cylinder and compressed at constant temperature? A. Number of collisions of oxygen molecules at per unit area of the wall of the cylinder increase. B. Oxygen (\[{{O}_{2}}\]) gets converted into ozone (\[{{O}_{3}}\]). C. Kinetic energy of the molecules of oxygen gas increases. |
| A. | A and C |
| B. | B and C |
| C. | C only |
| D. | A only |
| Answer» E. | |
| 280. |
Select the correct order of evaporation for water, alcohol, petrol and kerosene oil |
| A. | water > alcohol > kerosene oil > petrol |
| B. | alcohol > petrol > water > kerosene oil |
| C. | petrol > alcohol > water > kerosene oil |
| D. | petrol > alcohol > kerosene oil > water |
| Answer» E. | |
| 281. |
Which of the following is the best example of the law of conservation of mass? [NDA] |
| A. | When 12 gm. of carbon is heated in vacuum, there is no change in mass |
| B. | Weight of platinum wire is the same before and after heating |
| C. | A sample of air increases in volume when heated at constant pressure but mass remains unchanged |
| D. | 12 gm. of carbon combines with 32 gm. Of oxygen to, give 44 gm. of carbon dioxide. |
| Answer» B. Weight of platinum wire is the same before and after heating | |
| 282. |
In which one of the following situations a chemical reaction does not occur? [NDA] |
| A. | Common salt is exposed to air |
| B. | Coal is burnt in air |
| C. | Sodium is placed in water |
| D. | Iron is kept in moist air |
| Answer» B. Coal is burnt in air | |
| 283. |
Aluminium is used in thermite welding because - |
| A. | aluminium is a light metal |
| B. | aluminium has more affinity for oxygen |
| C. | aluminium is a strong oxidising agent |
| D. | aluminium is a reactive metal |
| Answer» C. aluminium is a strong oxidising agent | |
| 284. |
Removal of impurities from ore is known as - |
| A. | crushing and grinding |
| B. | concentration of ore |
| C. | calcination |
| D. | roasting |
| Answer» C. calcination | |
| 285. |
The atomic weights are expressed in terms of atomic mass unit. Which one of the following is used as a standard? [NDA] |
| A. | \[^{\text{1}}{{\text{H}}_{\text{1}}}\] |
| B. | \[^{\text{12}}{{C}_{6}}\] |
| C. | \[^{\text{16}}{{O}_{8}}\] |
| D. | \[^{35}C{{I}_{17}}\] |
| Answer» C. \[^{\text{16}}{{O}_{8}}\] | |
| 286. |
Which one of the following elements shows variable equivalent mass? [NDA] |
| A. | Zinc |
| B. | Silver |
| C. | Calcium |
| D. | Iron |
| Answer» E. | |
| 287. |
Which one of the following mixtures is homogeneous? [NDA] |
| A. | Starch and sugar |
| B. | Methanol and water |
| C. | Graphite and charcoal |
| D. | Calcium carbonate and calcium bicarbonate |
| Answer» C. Graphite and charcoal | |
| 288. |
Two elements gallium and oxygen combine to form a compound \[G{{a}_{2}}{{O}_{3}}\]. Which among the following is the valency of gallium? [NDA] |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» D. 4 | |
| 289. |
Which of the following salts are insoluble in water? [NDA] |
| A. | Chlorides of Fe and Mn |
| B. | Nitrates of Ag and Pb |
| C. | Carbonates of Pb and Cu |
| D. | Phosphates of Na and \[N{{H}_{4}}\] |
| Answer» D. Phosphates of Na and \[N{{H}_{4}}\] | |
| 290. |
Which one of the following salts when dissolved in water makes the solution basic? [NDA] |
| A. | Sodium chloride |
| B. | Copper sulphate |
| C. | Ferric chloride |
| D. | Sodium acetate |
| Answer» E. | |
| 291. |
The number of molecules in one mole of a gas is |
| A. | \[6.023\times {{10}^{23}}\] |
| B. | \[6.023\times {{10}^{22}}\] |
| C. | \[6.023\times {{10}^{21}}\] |
| D. | \[6.023\times {{10}^{20}}\] |
| Answer» B. \[6.023\times {{10}^{22}}\] | |
| 292. |
What is the mass (in grams) of 3 moles of N? |
| A. | 14 |
| B. | 28 |
| C. | 42 |
| D. | 56 |
| Answer» D. 56 | |
| 293. |
Which one among the following is an electrochemical cell that cannot be charged? [NDA] |
| A. | Electrolytic cell |
| B. | Storage cell |
| C. | Primary cell |
| D. | Fuel cell |
| Answer» D. Fuel cell | |
| 294. |
Which one among the following is the correct order of strength of acids? [NDA] |
| A. | \[{{H}_{2}}S{{O}_{4}}>{{H}_{3}}P{{O}_{3}}>C{{H}_{3}}COOH\] |
| B. | \[{{H}_{3}}P{{O}_{3}}>{{H}_{2}}S{{O}_{4}}>C{{H}_{3}}COOH\] |
| C. | \[C{{H}_{3}}COOH>{{H}_{3}}P{{O}_{3}}>{{H}_{2}}S{{O}_{4}}\] |
| D. | \[C{{H}_{3}}COOH>{{H}_{2}}S{{O}_{4}}>{{H}_{3}}P{{O}_{3}}\] |
| Answer» B. \[{{H}_{3}}P{{O}_{3}}>{{H}_{2}}S{{O}_{4}}>C{{H}_{3}}COOH\] | |
| 295. |
The following equation is an example of a redox reaction, in which \[C{{l}_{2}}\] is the oxidizing agent and \[FeB{{r}_{3}}\] is the reducing agent: \[2FeB{{r}_{3}}\,\,(aq)\,\,+\,\,3C{{l}_{2}}\,\,(g)=2FeCl\,{{\,}_{3}}(aq)\,\,+\,\,3B{{r}_{2}}\,\,(1)\] Which one among the following statements is incorrect for this redox reaction? [NDA] |
| A. | Oxidizing agents are themselves reduced |
| B. | Reducing agents gain or appear to gain electrons |
| C. | Reducing agents are themselves oxidized |
| D. | Oxidizing agents oxidize other substances |
| Answer» C. Reducing agents are themselves oxidized | |
| 296. |
Which one among the following is correct regarding \[{}^{20}Ne,{}^{23}N{{a}^{+}},{}^{19}{{F}^{-}}and\,\,{}^{24}M{{g}^{2+}}\]? [NDA] |
| A. | They are isomers of each other |
| B. | They are isotopes of each other |
| C. | They are isoelectronic with each other |
| D. | All of the above |
| Answer» D. All of the above | |
| 297. |
The number of protons in a negatively charged atom (anion) is [NDA] |
| A. | more than the atomic number of the element |
| B. | less than the atomic number of the element |
| C. | more than the number of electrons in the atom |
| D. | less than the number of electrons in the atom |
| Answer» E. | |
| 298. |
Which one among the following most correctly determines the atomic number of an element [NDA] |
| A. | Number of protons |
| B. | Number of protons and electrons |
| C. | Number of ions |
| D. | Number of nucleons |
| Answer» B. Number of protons and electrons | |
| 299. |
The oxide of which of the following elements is used as a coolant? |
| A. | Silicon |
| B. | Nitrogen |
| C. | Carbon |
| D. | Phosphorus |
| Answer» D. Phosphorus | |
| 300. |
Tails of comets are visible due to |
| A. | Tyndall Effect |
| B. | Reflection |
| C. | Brownian movement |
| D. | None of these |
| Answer» B. Reflection | |