Description : Electron-withdrawing groups are meta directors because : (a) the carbonium ion intermediate has a negative charge on the meta position. (b) the more stable resonance hybrid occurs with meta ... the electrophile. (d) the carbonium ion intermediate has a positive charge on the meta position
Last Answer : the more stable resonance hybrid occurs with meta attachment of the electrophile.
Description : Why does a H+ ion attacking a carbon-carbon double bond add to the carbon with the least number of substituents? (a) the reaction is resonance stabilized. (b) the hybrid geometry favors this ... tends to attack stable centers of negative charge. (d) a more stable carbonium ion is generated.
Last Answer : a more stable carbonium ion is generated.
Description : In the reaction of propene with HCl, H+ ion acts as the : (a) electrophile (b) carbonium ion (c) nucleophile (d) carbanion
Last Answer : electrophile
Description : Chlorine free radicals react with methane by : (a) donating their free-radical electron to methane to form chloromethane. (b) abstracting a hydrogen atom from methane, and producing ... produce chloromethane. (d) forming a carbonium ion intermediate that rapidly dissociates to form chloromethane
Last Answer : abstracting a hydrogen atom from methane, and producing HCl and a methyl radical
Description : Homolytic fission of covalent bond between carbon atoms will produce : (a) Two carbonium ions (b) Two molecules (c) Free radicals (d) Carbonium ion and carbanion
Last Answer : Free radicals
Description : In which of the following compounds, the `C-Cl` bond ion-isation shall give most stable carbonium ion?
Last Answer : In which of the following compounds, the `C-Cl` bond ion-isation shall give most stable carbonium ion? A. B. C. D.
Description : The compound which give the most stable carbonium ion on dehydration is
Last Answer : The compound which give the most stable carbonium ion on dehydration is A. `CH_(3) - underset(CH_(3)) ... underset(OH)underset(|)(CH)-CH_(2)CH_(3)`
Description : An aqueous solution of glycine is neutral because of the formation of : (a) Carbanion (b) Zwitterion (c) Carbonium ions (d) Free radicals
Last Answer : Zwitterion
Description : The mechanism of dehydration of an alcohol to give an ether involves formation of : (a) Carbonium ions (b) Carbanions (c) Free radicals (d) Carbenes
Last Answer : Carbonium ions
Description : The mechanism of dehydration of an alcohol to give an alkene involves formation of : (a) Carbonium ions (b) Carbanions (c) Free radicals (d) Carbenes
Description : The order of stability of carbonium ions is (a) tertiary > secondary > primary (b) secondary > tertiary > primary (c) primary > secondary > tertiary (d) primary > tertiary > secondary
Last Answer : tertiary > secondary > primary
Description : Homolytic fission of C–C bond leads to the formation of : (a) Free radicals (b) Carbonium ions (c) Carbanions (d) None of these
Description : CoCl2(en)2]+: Dichloridobis(ethylenediamine)Cobalt(III)ion. -Chemistry
Last Answer : Tetra amminechloridonitro cobalt (III) ion.
Description : Which complex ion is formed when undecomposed AgBr is washed with hypo solution in photography? (Comptt. All India 2013) -Chemistry
Last Answer : Sodium dithiosulphato argentate (I) complex is formed
Description : What are the advantages and disadvantages of LED storage cell and lithium ion batteries ?
Last Answer : Although both cells are rechargeable, lithium ion batteries have higher recharge efficiency. Due to this its use as an alternative to commercial led storage cell is increasing. Light Li / C anode and ... LiOH and H2, gases that are dangerous. LIB costs more than Ni-Cd rechargeable batteries .
Description : What is Lithium Ion Battery ( LIB) ?
Last Answer : Lithium-ion battery ( LIB) is a rechargeable battery. In this the Li + ion is transferred from the anode to the cathode during discharge and the same Li + ion from the cathode to the ... added ( Li +) graphite rod anode. Nowadays, its efficiency in applying nanotechnology has been greatly enhanced.
Description : What is Visitor Ion ?
Last Answer : : The ions that do not participate in the reaction of a reactant in a corner are called spectator ions.
Description : What is ion ?
Last Answer : When dissolved or dissolved in water, a large number of molecules of electrolytic matter are broken down into positive and negative charged particles. These electrically charged particles are called ions.
Description : Iron and manganese present as pollutants in water cannot be re-moved by - (1) oxidation followed by settling and filtration (2) chlorination (3) ion exchange process (4) lime soda process or manganese zeolite process
Last Answer : (2) chlorination Explanation: Water chlorination is the process of adding chlorine or hypochlorite to water. This method is used to kill certain bacteria and other microbes in tap water as chlorine is ... is used to prevent the spread of waterborne diseases such as cholera, dysentery, typhoid etc.
Description : What is the formula of potassium ion in the noble gas state? (1) K⁺ (2) K²⁺ (3) K²⁻ (4) K⁻
Last Answer : (1) K⁺
Description : The smallest particle of an element is called - (1) Ion (2) Electron (3) Atom (4) Molecule
Last Answer : (3) Atom Explanation: An element is a substance completely made up of one atom. However, the atom itself is not the smallest known particle, but instead each atom is made up of three individual parts: electrons, protons and neutrons.
Description : Which one of the following has a maximum tendency to form M^3 ion? (1) N (2) Bi (3) P (4) As
Last Answer : (1) N Explanation: Thee general electronic configuration of group 15 elements (N, P, As, Sb and Bi) is ns2np3. Since Nitrogen has smallest size and greatest electronegativity in the family, it may gain three electrons and attain noble has configuration, forming nitride N3- ions.
Description : Name the hydrogen ion which resembles anions of group 17.
Last Answer : A (H-) Hydride ion
Description : Identify the result of chemical reaction between permanganate ion and Br- ?
Last Answer : Ans. MnO2 and BrO3 - are formed.
Description : Discuss the Application of Solubility Product and common ion Effect?
Last Answer : Ans. (1) Calculation of solubility of sparingly soluble salts. (2) Predicting ionic or precipitation reaction. (3)In explaining salting out or precipitation of soluble salts. (4) In qualitative analysis. (5) In fractional precipitation.
Description : Give one example for each of the following types of inter-particle forces (a) London dispersion forces (b)Dipole-Dipole forces (c) Hydrogen bond (d) Ion-dipole forces
Last Answer : Ans. (a) noble gases. (b) between HCl molecules. (c) Between water molecules or HF molecules. (d)Between NO3- and water molecules.
Description : What is Zwitter ion? Write the formula of Zwitter ion of alanine.
Last Answer : Ans:- The ion of a molecule having +ve change at one end and –ve charge at other is called zwitter ion.
Description : Why cyanide ion act as ambident nucleophile ?
Last Answer : Ans.---- Cyanide ion can link through either carbon or nitrogen, therefore it is an ambident nuclophile.
Description : Ortho and paranitrophenols are more acidic than phanel. Draw the resonance structures of the corresponding phonoxide ion.
Last Answer : Ans:- Electronwithdrawal by nitro group makes the plenoxide ion more resonance stabilized and so the strength of phenel increases.
Description : What is the hybridisation of central metal ion and shape of Wilkinson’s catalyst ?
Last Answer : Wilkinson’s catalyst is (PH3 P)3 RhCl. In this Rh has dsp² hybridisation and square planar shape.
Description : How many EDTA (lethylendiamine tetra acetic acid) molecules are required to make an octahedral complex with a Ca2+ ion.
Last Answer : EDTA is a hexadentate ligand therefore only one EDTA molecule is required to form octahedral complex.
Description : FeSO4 solution mixed with (NH4 ) 2 SO4 solution in 1 : 1 molar ratio gives the test of Fe2+ ion but CuSO4 solution mixed with aqueous ammonia in 1 : 4 molar ratio does not give the test of Cu2+ ion. Explain why ?
Last Answer : When FeSO4 and (NH4 ) 2 SO4 solution are mixed in 1 : 1 molar ratio, a double salt is formed. It has the formula FeSO4 (NH4 ) 2 SO4 . 6 H2O. In aqueous solution, the salt dissociates. When CuSO4 and NH3 are mixed in the molar ratio of 1 : 4 in solution, a complex [Cu (NH3 ) 4 ] SO4 is formed.
Description : (a) If the radius of the Br ion is 0.182 nm, how large a cation can fit in each of the tetrahedral hole. (b) AgI crystallizes in a cubic closed packed ZnS structure. What fraction of tetrahedral site ... Ag ion ? (c) At what temp. range, most of the metals becomes super conductors ?
Last Answer : (a) For a tetrahedron the limiting ratio is 0.225 – 0.414 For largest cation highest value 0.414 would be considered. r + / r– = 0.414 r + = 0.414 × 0.182 = 0.075 nm. (b) In FCC there are 8 tetrahedral voids. Out of this ½ is occupied by Ag cation. (c) 2 k – 5 k.
Description : Which of the following is not a correct statement concerning the FriedelCrafts acylation of benzene? (a) An alkyl group substitutes for a hydrogen. (b) The benzene ring attacks an acylium ion. (c) The acylium ion is resonance stabilized. (d) The acylium ion is often produced from an acyl chloride.
Last Answer : An alkyl group substitutes for a hydrogen
Description : A zwitterion is (a) an ion that is positively charged in solution (b) an ion that is negatively charged in solution (c) a compound that can ionize both as a base and an acid. (d) a carbohydrate with an electrical charge.
Last Answer : a compound that can ionize both as a base and an acid
Description : The N–H bond in the ammonium ion, NH4+, is formed by the overlap of what two orbitals? (a) sp3–sp3 (b) sp3–sp2 (c) sp2–sp2 (d) sp3–s
Last Answer : sp3–s
Description : Amides undergo hydrolysis under acidic conditions to give (a) Carboxylic acid and amine (b) Carboxylic acid and ammonium ion (c) Carboxylate ion and ammonium ion (d) Carboxylate ion and amine
Last Answer : Carboxylic acid and ammonium ion
Description : Which of the following statements describes the first step in the mechanism of the aldol condensation? (a) An alpha hydrogen is abstracted by the base to form an enolate anion. (b) A nucleophilic base attacks ... by the base ion. (d) The alpha hydrogen is abstracted by an acid to the enolate anion.
Last Answer : An alpha hydrogen is abstracted by the base to form an enolate anion
Description : The greater acidity of carboxylic acids compared to alcohols arises primarily from : (a) the electron-donating effect of the hydroxyl group (b) the electron-withdrawing effect of the carboxyl ... of α-hydrogens of carboxylic acids (d) the resonance stability associated with the carboxylate ion
Last Answer : the resonance stability associated with the carboxylate ion
Description : What is the strongest intermolecular force present in liquid ethanol? (a) induced dipole-induced dipole (b) dipole-dipole, specifically hydrogen bonding (c) dipole-dipole, but not hydrogen bonding (d) ion-dipole
Last Answer : dipole-dipole, specifically hydrogen bonding
Description : In the reaction of ethylene with H2O in the presence of sulfuric acid, which one adds across the double bond first? (a) H+ (b) H. (c) HO– (d) sulfate ion
Last Answer : H+
Description : The concentraction of hydrogen ion (H+ )is denoted by pH.How do you denote concentration of hydrogen ion(OH)?
Last Answer : Ans:The concentration of hydrogen ion (OH) is denoted by poH.
Description : Which one of the following statements about the mass spectrum of CH3Br is correct? a. the last two peaks are of equal size and occur at m/z values of 94 and 96 b. the last two peaks have abundances in the ... m/z value of 95 d. there is just one peak for the molecular ion with an m/z value of 44
Last Answer : a. the last two peaks are of equal size and occur at m/z values of 94 and 96
Description : In an alkyl halide substitution of hydrogen by deuterium results in slow formation of ion pair. This is known as? a. Ortho effect b. Mesomeric effect c. Secondary kinetic isotope effect d. Primary kinetic isotope effect
Last Answer : c. Secondary kinetic isotope effect
Description : Which is smaller in size between a metal ion and its parent atom?
Last Answer : The monovalent ions (M+ ) are smaller than the parent atom.
Description : Which force is most important in allowing ammonia, NH3, to dissolve in water? A hydrogen bonding B dipole-induced dipole C ion-dipole D dipole-dipole E ionic
Last Answer : A hydrogen bonding
Description : How many electrons are there in the valence shell of the O2– ion? A 2 B 8 C 10 D 16 E 18
Last Answer : B 8
Description : What is the purpose of the salt bridge in an electrochemical cell? w) It allows ion migration. x) It allows electron flow. y) It prevents ion migration. z) It prevents electron flow.
Last Answer : ANSWER: W -- IT ALLOWS ION MIGRATION
Description : Which of the following terms denotes the polar molecules or negative ions clustered about a central positive ion? w) ligands x) isomers y) complex ions z) dipoles
Last Answer : ANSWER: W -- LIGAND
Description : The boiling points of the halogens increase going from F2 to I2. What type of intermolecular forces are responsible for this trend? w) permanent dipole x) hydrogen bonding y) ion-ion attraction z) London dispersion forces
Last Answer : ANSWER: Z -- LONDON DISPERSION FORCES