Description : The modern atomic theory was conceived by : w) Victor Grignard x) Daniel Rutherford y) Svante Arrhenius z) John Dalton
Last Answer : ANSWER: Z -- JOHN DALTON
Description : Name the person who developed a table of elements which revealed regularities in elemental properties in 1869? w) Theodore Richards x) Antoine Lavoisier y) Dmitri Mendeleev z) Svante Arrhenius
Last Answer : ANSWER: Y -- DMITRI MENDELEEV
Description : Which of the following scientists was awarded the Nobel Prize in 1911 for the discovery of the radioactive elements, radium and polonium? w) John Dalton x) Dmitri Mendeleev y) Emil Fischer z) Marie Curie
Last Answer : ANSWER: Z -- MARIE CURIE
Description : Grignard reagents do not show any reaction with (a) Alkoxyalkanes (b) Alkanones (c) Alkyl alkanoates (d) Acyl halides
Last Answer : Alkoxyalkanes
Description : What was arranged into a systemic chart by Dmitri mendeleev?
Last Answer : Feel Free to Answer
Description : What did Dmitri mendeleev have to do to unlock the hidden pattern of the elements?
Last Answer : What is the answer ?
Description : Dmitri Mendeleev created the what?
Last Answer : Periodic table
Description : Who proposed first atomic theory? (1) E. Rutherford (2) De Broglie (3) John Dalton (4) D. I. Mendeleev
Last Answer : (3) John Dalton Explanation: Democritus first suggested the existence of the atom but it took almost two millennia before the atom was placed on a solid foothold as a fundamental chemical object by John Dalton (1766-1844).
Description : Mendeleev proposed the existence of an unknown element that he called eka-aluminum. The element is now called: w) magnesium x) silicon y) gallium z) germanium
Last Answer : ANSWER: C -- GALLIUM
Description : Which of the following refers to the scattering of light by colloidal particles? w) Rutherford effect x) Tyndall effect (pron: tin-dahl) y) Thompson effect z) none of these
Last Answer : ANSWER: X -- TYNDALL EFFECT
Description : Who invented the barometer? w) Torricelli x) Avogadro y) Rutherford z) Becquerel
Last Answer : ANSWER: W -- TORRICELLI
Description : The idea that electrons revolved in orbits around the nucleus of an atom without radiating energy away from the atom was postulated by: w) Thompson x) Bohr y) Rutherford z) Einstein
Last Answer : ANSWER: X -- BOHR
Description : Modern periodic law had been given by (1) Moseley (2) Mendeleev (3) Lother-Mayer (4) Lavoisier
Last Answer : (1) Moseley Explanation: In 1913, H.G.J Moseley in England proved that the more fundamental properties of an element are its atomic number. Therefore he suggested that the basis of classification of elements should be atomic number.
Description : What is Grignard reagent?
Last Answer : Ans. Alkyl magnesium halides
Description : Explain why Grignard reagents do not reacts with alkanes.
Last Answer : Ans. In alkanes , the C – H bond has very little polarity . The hydrogen cannot be abstracted by the Grignard reagent.
Description : Why are Grignard reagents soluble in ether but not in benzene ?
Last Answer : Ans. Grignard reagents from co-ordination complexes with ether but not benzene since the former has lone pair of electrons but the later does not.
Description : Which reaction does not yield an ester as one of the products? (a) A carboxylic acid is heated with an alcohol (b) A Grignard reagent is added to a carboxylic acid (c) An acid halide is treated with an alcohol (d) An alkyl halide is heated with the salt of a carboxylic acid
Last Answer : A Grignard reagent is added to a carboxylic acid
Description : Which of the following reagents will react readily with both aldehydes and ketones? (a) Grignard reagent (b) Fehling's reagent (c) Tollens' reagent (d) Schiff's reagen
Last Answer : Grignard reagent
Description : Which of the following alcohols can be prepared by the reaction of methyl formate with excess Grignard reagent? (a) 1-pentanol (b) 2-pentanol (c) 3-pentanol (d) 2-methyl-2-pentanol
Last Answer : 3-pentanol
Description : Which of the following is correct? (a) When a Grignard reagent reacts with a ketone, the addition product is a primary alcohol. (b) When a Grignard reagent reacts with a ketone, the addition product ... with a aldehyde, the addition product is a tertiary alcohol. (d) None of the above are correct.
Last Answer : None of the above are correct.
Description : Ketones react with Grignard reagents to form an addition product which on hydrolysis gives a (a) Primary alcohol (b) Tertiary alcohol (c) Secondary alcohol (d) Ketal
Last Answer : Tertiary alcohol
Description : The Grignard reagent, CH3CH2MgBr, can be used to prepare (a) Ethane (b) 3-Ethyl-3-pentanol (c) Propanoic acid (d) All of these
Last Answer : All of these
Description : The disappearance of the purple color of KMnO4 in its reaction with alkene is known as (a) Markovnikov test (b) Grignard test (c) Baeyer test (d) Wurtz test
Last Answer : Baeyer test
Description : [SPOILER ALERT!] If you read The Brothers Karamazov, do you think Dmitri killed his father?
Last Answer : Great book, by the way…
Description : This scientist gave the law- ‘Properties of elements are a periodic function of their atomic number.’ This property of the fundamental importance of atomic number was discovered by- (1) Johann Wolfgang Döbereiner (2) John Newlands (3) Dmitri lvanovich Mendeléev (4) Henry Moseley
Last Answer : (4) Henry Moseley Explanation: In 1913, Henry Moseley showed that the atomic number of an element is a more fundamental property than its atomic mass as described below.
Description : In organic compounds, nitrogen is estimated by – (1) Carius method (2) Victor-Meyees method (3) Liebigs method (4) Dumas' method
Last Answer : (4) Dumas' method Explanation: In Dumas' method, a known quantity of nitrogen containing organic compound is heated strongly with excess of copper oxide in an atmosphere of carbon dioxide to produce free nitrogen in addition to carbon dioxide and water.
Description : In organic compounds, nitrogen is estimates by - (1) Dumas method (2) Carius method (3) Victor-meyer's method (4) Liebig's method
Last Answer : (1) Dumas method
Description : The nitrogen content of proteins can be quantitatively determined by (a) Carius method (b) Kjeldahl's method (c) Victor Meyer's method (d) Rast method
Last Answer : Kjeldahl's method
Description : In organic compounds, nitrogen is estimated by (1) Carius method (2) Victor-Meyer’s method (3) Liebig’s method (4) Dumas’ method
Last Answer : Dumas’ method
Description : Grignard reagent is chemically known as (A) Ethyl magnesium chloride (B) Methyl magnesium chloride (C) Dichlorophenol (D) Monochloroacetic acid
Last Answer : (A) Ethyl magnesium chloride
Description : Chemical name of Grignard reagent is (A) Sodium thiosulphate (B) Ethyl magnesium chloride (C) Sodium sulphite (D) Sodium bicarbonate
Last Answer : (B) Ethyl magnesium chloride
Description : Who invented the modern Periodic table? (1) Faraday (2) Mendeleev (3) Newton (4) Bohr
Last Answer : (2) Mendeleev Explanation: Dmitri Mendeleev was a Russian chemist who developed the periodic classification of the elements in 1869 A.D.
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 are isotopes not considered in Mendeleev’s periodic table?Name the elements which are predicted by Mendeleev as eka –silicon and eka –aluminum
Last Answer : Ans.Because Mendeleev gave priority to similarities in properties. Germanium and gallium
Description : What are the important features of Mendeleev periodic table?
Last Answer : Ans: based on(i) increasing atomic mass (ii) similarities in properties of elements.(iii) 63 elements divided in 7 horizontal row called periods and 8 vertical groups
Description : State Mendeleev Periodic Law.
Last Answer : Ans: The chemical and physical properties of the elements are periodic functions of their atomic masses.
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 : Metal sulphides occur mainly in rocks and metal halides in lakes and seas. Explain.
Last Answer : Ans.: Metal halides being soluble in water, get dissolved in rain water and are carried to lakes and seas during weathering of rocks. On the otherhand, metal sulphides being insoluble are left behind in the rocks as residue.
Description : Give reason for the appearance of colour in alkali metal halides.
Last Answer : Due to F-centres.
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 : 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 : 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 : The substance whose chemical formula is CH3OH is known as w) carbonated water x) grain alcohol y) potable alcohol z) methanol
Last Answer : ANSWER: Z -- METHANOL