Description : The term "Doab" means – (1) a land between two mountains (2) a land between two lakes (3) a land between two rivers (4) a land between two seas
Last Answer : (3) a land between two rivers Explanation: Doab is a term used in India and Pakistan for the "tongue," or tract of land lying between two converging, or confluent, rivers. It is similar to an ... to the confluence of two rivers (esp. that between the Ganges and Jumna). Physical Geography (Set: 04)
Description : Sludge banks are formed if sewage is disposed of in A. Rivers B. Seas C. Lakes D. None of these
Last Answer : ANS: B
Description : The term “Doab” means (1) a land between two mountains (2) a land between two lakes (3) a land between two rivers (4) a land between two seas
Last Answer : a land between two rivers
Description : which of the following sulphides cannot be reduced to metal by `H_(2)`at about `1000^(@)`C?
Last Answer : which of the following sulphides cannot be reduced to metal by `H_(2)`at about `1000^(@)`C? A. HgS B. PbS C. `CS_(2)` D. `Bi_(@)S_(3)`
Description : Give reason for the appearance of colour in alkali metal halides.
Last Answer : Due to F-centres.
Description : If water contracts on freezing, which of the following would happen? (a) Icebergs will completely float on the surface of water (b) Ice would become more dense (c) Lakes would freeze from top to bottom (d) Rocks will crack due to freezing of internal water
Last Answer : Ans:(b)
Description : The source of maximum sulphur is in (a) Oceans (b) Land (c) Rocks (d) Lakes
Last Answer : (c) Rocks
Description : Formation of which of the sulphides is most spontaneous?
Last Answer : Formation of which of the sulphides is most spontaneous? A. HgS B. `Bi_(2)S_(3)` C. PbS D. `Cs_(2)`
Description : Which one of the following basic radical (s) `is//are ` precipitated as sulphides in acidic medium in qualitative analysis?
Last Answer : Which one of the following basic radical (s) `is//are ` precipitated as sulphides in acidic medium in qualitative analysis ... `Cd^(2+)` D. `Zn^(2+)`
Description : The commonest form of iron & manganese found in ground water as pollutant is in the form of their (A) Carbonates (B) Bi-carbonates (C) Chlorides (D) Sulphides
Last Answer : (B) Bi-carbonates
Description : Fluorosis (a bone disease) is caused by the presence of high concentration of __________ in atmospheric air. (A) Hydrocarbons (B) Hydrogen fluoride (C) Hydrogen sulphides (D) Nitrogen dioxide
Last Answer : (B) Hydrogen fluoride
Description : Which of the following is an yellow pigment? (A) Titanium dioxide (B) Ferrous sulphate (C) Lead chromates (D) Zinc sulphides
Last Answer : (C) Lead chromates
Description : Presence of carbonaceous matter in the sewage (A) Causes reduction in its dissolved oxygen content thereby endangering the life of aquatic creatures (B) Reduces sulphate ions to sulphides causing obnoxious ... quantity of chlorine used for its purification (D) All (A), (B) and (C)
Last Answer : (D) All (A), (B) and (C)
Description : Pick up the incorrect statement from the following: (A) Iron salts produce heavy flocks and hence remove more suspended matter (B) Iron salts remove hydrogen sulphides (C) Iron salts can be used over a limited range of pH values (D) Iron salts impart corrosiveness to water
Last Answer : (C) Iron salts can be used over a limited range of pH values
Description : Mathamoglobinemia or blue baby disease is caused due to (A) Chlorides (B) Nitrites (C) Nitrates (D) Sulphides
Last Answer : (C) Nitrates
Description : Root exudates of wheat and oats which has detrimental effects on wild mustard con tain a). Phenolic acid b). Alkaloids c). Sulphides d). Lactones
Last Answer : a). Phenolic acid
Description : Silver halides are used in photographic plates because they are - (1) oxidised in air (2) soluble in hyposolution (3) reduced by light (4) totally colourless
Last Answer : (3) reduced by light Explanation: The light-sensitive chemicals used in photographic film and paper are silver halides. Silver halides are used in photographic film and photographic paper, including ... - meaning that it can undergo development which turns the entire crystal into metallic silver.
Description : Why the presence of a base is essential in the ammonolysis of alkyl halides ?
Last Answer : During ammonolysis of alkyl halides, the acid liberated during the reaction combines with the amine formed to form amine salt. To liberate free amine from the amine salt, a base is needed.
Description : When ammonia is added to an alkyl halide, in the presence of base : (a) primary amines form (b) amides form (c) nitrated alkyl halides form (d) quaternary ammonium salts form
Last Answer : primary amines form
Description : Aryl halides are less reactive towards nucleophilic substitution as compared to alkyl halides due to (a) Inductive effect (b) Resonance stabilization (c) Tautomerism (d) Stereoisomerism
Last Answer : Resonance stabilization
Description : Alkyl halides react with ammonia in the presence of base to form : (a) primary amines (b) nitrated alkyl halides (c) amides (d) quaternary ammonium salts
Last Answer : primary amines
Description : Grignard reagents do not show any reaction with (a) Alkoxyalkanes (b) Alkanones (c) Alkyl alkanoates (d) Acyl halides
Last Answer : Alkoxyalkanes
Description : Which of the following halides is least reactive in an E2 reaction with sodium methoxide? (a) (CH3)3CCH2I (b) (CH3)2CHCHICH3 (c) (CH3)2CHCH2Br (d) (CH3)2CHCH2Cl
Last Answer : (CH3)3CCH2I
Description : Which of the following halides is most reactive in an E2 reaction with sodium methoxide? (a) (CH3)3CCH2I (b) (CH3)2CHCHICH3 (c) (CH3)2CHCH2Br (d) (CH3)2CHCH2C
Last Answer : (CH3)2CHCHICH3
Description : Which of the following statements concerning SN2 reactions of alkyl halides is not correct? (a) The rate of reaction depends on the concentration of the nucleophile. (b) The rate of reaction depends on the ... carbon of the C-Br bond. (d) All alkyl iodides react more rapidly than all alkyl chlorides
Last Answer : All alkyl iodides react more rapidly than all alkyl chlorides
Description : Which of the following is not correct concerning substitution and elimination reactions of alkyl halides? (a) The electrophile replaces the leaving group. (b) Compounds containing electron-donating groups bonded to an ... replaced by another atom or group in substitution reactions. (d) (a) and (b)
Last Answer : (a) and (b)
Description : Which alkyl halides react most readily by nucleophilic substitution? (a) CH3CH2Cl (b) CH3CH2I (c) CH3CH2Br (d) CH3CH2F
Last Answer : CH3CH2I
Description : Alkyl halides undergo (a) Electrophilic substitution reactions (b) Electrophilic addition reactions (c) Nucleophilic substitution reactions (d) Nucleophilic addition reactions
Last Answer : Nucleophilic substitution reactions
Description : Whose name is given to alkylmagnesium halides: w) Victor Grignard x) Daniel Rutherford y) Dmitri Mendeleev
Last Answer : ANSWER: W -- VICTOR GRIGNARD
Description : Silver halides are used in photographic plates because they are (1) oxidised in air (2) soluble in hyposolution (3) reduced by light (4) totally colourless
Last Answer : reduced by light
Description : Basophilic prokaryotes (a) grow and multiply in very deep marine sediments (b) occur in water containing high concentrations of barium hydroxide (c) readily grow and divide in sea water enriched in any soluble salt of barium (d) grow slowly in highly alkaline frozen lakes at high altitudes.
Last Answer : (a) grow and multiply in very deep marine sediments
Description : I will be describing a chemical element. Try to identify it with the fewest number of clues. This chemical element is a silver-white metal, with bluish tinge, capable of taking a high polish. T element ... crust and used to make drink cans. The atomic number of this element is 13. Name t element.
Last Answer : ANSWER: ALUMINUM
Description : From which rocks is the soil material mainly derived? -Do You Know?
Last Answer : answer:
Description : Which one among the following statements regarding India's coal is not correct? [CDS 2012] (a) 98 percent of reserves of coal in India belongs to Gondwana period (b) Unknown amount of coal ... Tertiary rocks (d) Gondwana coal is mainly found in the river valleys of Damodar, Mahanadi and Godavari
Last Answer : Ans: (c)
Description : From which rocks is the soil material mainly derived
Last Answer : Sedimentary rocks
Description : Granite mainly composed of quartz and feldspar particles, is obtained from (A) Sedimentary rocks (B) Metamorphic rocks (C) Igneous rocks (D) All the above
Last Answer : Answer: Option C
Description : 1. With which does the power to extend or restrict the jurisdiction of the High Court rest? 2. Gobar gas' contains mainly which gas? 3. Which is the biggest Public Sector undertaking in the ... the Pacific Ocean)? 20. At which one place did Mahatma Gandhi first start his Satyagraha in India?
Last Answer : Answer : 1. With the Parliament 2. Methane3. Railways 4. Limestone 5. Polak 6. By its octane number 7. Rabies virus 8. President 9. Extreme heat and pressure 10. Mahatma Gandhi 11. -40° 12. French ... Ocean 15. Mahatma Gandhi 16. Parmelia 17. 65 years 18. Quartz glass 19. 11,033 m 20. Champaran
Description : Which of the following halides has the maximum covalent character ?
Last Answer : Which of the following halides has the maximum covalent character ? A. LiI B. NaI C. KI D. CsI
Description : Best method for preparing primary amines from alkyl halides without changing the number of carbon atoms in the chain is
Last Answer : Best method for preparing primary amines from alkyl halides without changing the number of carbon atoms in ... reaction D. Reaction with `NH_(3)`
Description : Number of halides undergoing complete reaction in presence of water under normal conditions is : (i) `BF_(3)` (ii) `BCl_(3)` (iii) `NCl_(3)` (iv) `AlC
Last Answer : Number of halides undergoing complete reaction in presence of water under normal conditions is : (i) `BF_(3)` (ii ... (vi) `PCl_(3)` (vii) `AsCl_(3)`
Description : The order of stability of halides of sulphur with different halogens is
Last Answer : The order of stability of halides of sulphur with different halogens is A. `I^(-) gt Br^(-) gt Cl^(-) gt F^(-)` ... `F^(-) gt Cl^(-) gt I^(-) Br^(-)`
Description : Which of the following hydrogen halides react with `AgNO_3` to give a precipitate that dissolves in hypo solution ? (I)HCl (II)HF (III)HI (IV)HBr
Last Answer : Which of the following hydrogen halides react with `AgNO_3` to give a precipitate that dissolves in hypo solution ? (I) ... II),(I) D. (II),(IV),(III)
Description : The correct order of the thermal stability of hydrogen halides `(H-X)` is
Last Answer : The correct order of the thermal stability of hydrogen halides `(H-X)` is A. (1) HI gt HBrgt HCI gt HF B. ... HBr lt HI D. (4)Hl gt HCI lt HF lt HBr
Description : Pseudo halides are anions having resemblance with halide ions. Group I metals can form salts with pseudo halides. Pseudo halogens can acts as ligands
Last Answer : Pseudo halides are anions having resemblance with halide ions. Group I metals can form salts with pseudo halides. ... and C black D. `Na(CN)_2^-`
Last Answer : Pseudo halides are anions having resemblance with halide ions. Group I metals can form salts with pseudo halides. ... NaBr C. (C) NaF D. (D) Nal
Last Answer : Pseudo halides are anions having resemblance with halide ions. Group I metals can form salts with pseudo halides. ... . H_2O` D. (D) None of these
Last Answer : Pseudo halides are anions having resemblance with halide ions. Group I metals can form salts with pseudo halides ... . `NaCN, NaOCN` D. `HCOONa, NH_3`