Question

Question. What would be the reactant and reagent used to obtain 2, 4-dimethyl pentan-3-ol(a) Propanal and propyl magnesium bromide(b) 3-methylbutanal and 2-methyl magnesium iodide (c) 2-dimethylpropanone and methyl magnesium iodide(d) 2- methylpropanal and isopropyl magnesium iodide Answer: (d) 2- methylpropanal and isopropyl magnesium iodide

Question. Which one of the following are correctly arranged on the basis of the property indicated: (a)I2< Br2<F2<Cl2 [ increasing bond dissociation enthalpy] (b) H2O > H2S<H2Te<H2Se [ increasing acidic strength] (c) NH3 < N2O< NH2OH<N2O5 [ increasing oxidation state] (d) BiH3<SbH3<AsH3<PH3<NH3 [ increasing bondangle] Answer: (d) BiH3<SbH3<AsH3<PH3<NH3 [ increasing bondangle] correct order

Question. A unit cell of NaCl has 4 formula units. Its edge length is 0.50 nm. Calculate the density if molar mass of NaCl = 58.5 g/mol.(a) 1 g/cm3(b)2 g/ cm3 (c) 3 g/ cm3 (d)4g/ cm3 Answer: (c) 3g/ cm3

Question. In lake test for Al3+ ions, there is the formation of coloured ‘floating lake’. It is due to: (a)Absorption of litmus by [Al(OH)4]– (b)Absorption of litmus by Al(OH)3 (c)Adsorption of litmus by [Al(OH)4]– (d) Adsorption of litmus by Al(OH)3 Answer: (d) Adsorption of litmus by Al(OH)3

Question. In the following reaction,identify A and B: B (a) A= COOH-(CH2)4 -COOH, B= OHC-(CHOCOCH3)4 -CH2OCOCH3(b) A= COOH-(CH2)4 -CHO , B= OHC-(CHOCOCH3)4 -CH2OCOCH3(c) A= OHC-(CHOCOCH3)3-CH2OCOCH3 B= COOH-(CH2)4 -CHO ,(d) A= OHC-(CHOCOCH3)4-CH2OCOCH3 B= COOH-(CH2)4 -COOH Answer: (d) A= OHC-(CHOCOCH3)4-CH2OCOCH3 B= COOH-(CH2)4 -COOH

Question. Water retention or puffiness due to high salt intake occurs due to:(a)diffusion(b)vapour pressure difference(c) osmosis(d)reverse osmosis Answer: (c) Osmosis

Question. Ozone is a/ an _____ molecule and the two O-O bond lengths in ozone are (i)_____and (ii) ______(a) linear ,110pm ; 148pm(b) angular, 110pm ; 148pm(c)linear, 128pm ; 128pm(d)angular, 128pm ; 128pm Answer: (d)angular, 128pm ; 128pm (Ozone is a resonance hybrid of two equivalent structures)

Question. The reaction of toluene with Cl2 in presence of FeCl3 gives ‘X’ while theof toluene with Cl2in presence of light gives ‘Y’. Thus ‘X’ and ‘Y’ are:(a) X = benzyl chloride Y = o and p – chlorotoluene(b) X = m – chlorotoluene Y = p – chlorotoluene(c) X = o and p–chlorotoluene Y

Question. Metal M ions form a ccp structure. Oxide ions occupy 1⁄2 octahedral and 1⁄2 tetrahedral voids. What is the formula of the oxide?(a)MO(b)MO2(c)MO3(d) M2O3 Answer: (d) M2O3 Metal M ions form ccp structure. Let number of ions of M be : XNo. of tetrahedral voids = 2xNo. of octahedral voids = xNumber of oxide

Question. Which of the following has highest ionisation enthalpy?(a)Nitrogen(b)Phosphorus(c)Oxygen(d)Sulphur Answer: (a)Nitrogen (High IE of N is because of smallest size in the group and completely half – filled p subshell)