Practice Questions

Q48.For a first order reaction, (A) → products, the concentration of A changes from 0.1 M to 0.025 M in 40 minutes. The rate of reaction when the concentration of A is 0.01 M is : (1) 1.73 × 10−5M/min (2) 3.47 × 10−4M/min (3) 3.47 × 10−5M/min (4) 1.73 × 10−4M/min

Q48.A solid has a ' bcc ' structure. If the distance of nearest approach between two atoms is 1.73Å, the edge length of the cell is (1) 314.20pm (2) 1.41pm (3) 200pm (4) 216pm

Q49.The activation energy for a reaction which doubles the rate when the temperature is raised from 298 K to 308 K is (1) 59.2 kJ mol−1 (2) 39.2 kJ mol−1 (3) 52.9 kJ mol−1 (4) 29.5 kJ mol−1

Q49.For a reaction A → Products, a plot of log t1/2 versus log a0 is shown in the figure. If the initial concentration of A is represented by a0 , the order of the reaction is (1) one (2) zero (3) two (4) three

Q50.In a chemical reaction A is converted into B. The rates of reaction, starting with initial concentrations of A as 2 × 10−3M and 1 × 10−3 M, are equal to 2.40 × 10−4Ms−1 and 0.60 × 10−4Ms−1 respectively. The order of reaction with respect to reactant A will be (1) 0 (2) 1.5 (3) 1 (4) 2

Q50.On addition of 1 mL of 10%NaCl solution to 10 mL gold sol in the presence of 0.025 g of starch, the coagulation is just prevented. Starch has gold number JEE Main 2012 (19 May Online) JEE Main Previous Year Paper (1) 2.5 (2) 25 (3) 0.25 (4) 0.025

Q51.Iron exhibits +2 and +3 oxidation states. Which of the following statements about iron is incorrect? JEE Main 2012 (Offline) JEE Main Previous Year Paper (1) Ferrous oxide is more basic in nature than the (2) Ferrous compounds are relatively more ionic than ferric oxide. the corresponding ferric compounds (3) Ferrous compounds are less volatile than the (4) Ferrous compounds are more easily hydrolysed corresponding ferric compounds. than the corresponding ferric compounds.

Q51.Reaction rate between two substance A and B is expressed as following: rate = k[A]n[B]m If the concentration of A is doubled and concentration of B is made half of initial concentration, the ratio of the new rate to the earlier rate will be: (1) m + n (2) n −m (3) 1 (4) 2(n−m) 2(m+n)

Q52.Extraction of zinc from zinc blende is achieved by (1) roasting followed by self-reduction (2) electrolytic reduction (3) roasting followed by reduction with carbon (4) roasting followed by reduction with another metal

Q52.Which among the following will be named as dibromidobis (ethylene diamine)chromium(III) bromide? (1) [Cr(en)3]Br3 (2) [Cr(en)2Br2]Br (3) [Cr( en )Br4]− (4) [Cr(en)Br2]Br

Q53.Magnetic moment of Gd3+ ion (Z = 64) is (1) 3.62 BM (2) 9.72BM (3) 7.9 BM (4) 10.60BM

Q53.How many chiral compounds are possible on monochlorination of 2−methyl butane ? (1) 8 (2) 2 (3) 4 (4) 6

Q53.Reagent used to convert allyl alcohol to acrolein is (1) MnO2 (2) H2O2 (3) OsO4 (4) KMnO4

Q53.The d-electron configurations of Cr2+, Mn2+, Fe2+ and Co2+ are d4, d5, d6 and d7 respectively. Which one of the following will exhibit the lowest paramagnetic behaviour? (Atomic no. Cr = 24, Mn = 25, Fe = 26, Co = 27 ). (1) [Co(H2O)6]2+ (2) [Cr(H2O)6]2+ (3) [Mn(H2O)6]2+ (4) [Fe(H2O)6]2+

Q53.Which of the following forms stable +4 oxidation state? (1) La(Z = 57) (2) Eu(Z = 63) (3) Ce(Z = 58) (4) Gd(Z = 64)

Q54.Which is not the correct Statement? (At. nos. Ce = 58, Lu = 71, La = 57, Yb = 70 ) (1) Colour of Yb3+ ion is pink. (2) La3+ is diamagnetic. (3) Ce4+ has f 0 configuration. (4) Lu3+ had f 14 configuration. JEE Main 2012 (07 May Online) JEE Main Previous Year Paper

Q54.The number of unpaired electrons in Gadolinium [Z = 64] is (1) 3 (2) 8 (3) 6 (4) 2

Q54.Which of the following complex ions will exhibit optical isomerism? (en = 1, 2-diamine ethane). (1) [Cr(NH3)2Cl2]+ (2) [Co(en)2Cl2]+ (3) [Co(NH3)4Cl2]+ (4) [Zn(en)2]2+

Q55.Which of the following statements is wrong? (1) Ethyl chloride on reduction with Zn −Cu couple (2) The reaction of methyl magnesium bromide with and alcohol gives ethane. acetone gives butanol-2. (3) Alkyl halides follow the following reactivity (4) C2H4Cl2 may exist in two isomeric forms sequence on reaction with alkenes. R −I > R −Br > R −Cl > R −I

Q55.Square-planar geometry is shown by (1) [PtCl2(NH3)2] (2) [NiCl4]2− (3) MnO−4 (4) CrO2−4

Q55.How many cyclic structures are possible for C4H6 ? (1) 3 (2) 5 (3) 6 (4) 4

Q56.lodoform can be prepared from all except : (1) Ethyl methyl ketone (2) Isopropyl alcohol (3) 3−Methyl −2− butanone (4) Isobutyl alcohol

Q56.The major product obtained in the photobromination of 2-methyl butane is (1) 2-bromo-2-methylbutane (2) 1-bromo-2-methylbutane (3) 1-bromo-3-methylbutane (4) 2-bromo-3-methylbutane

Q56.The most basic compound among the following is (1) Acetanilide (2) Benzylamine (3) p-Nitro aniline (4) Aniline AgCNQ57. ⟶X Reduction⟶ Y , Here Y is C2H5Br Zn−Rg/HCl (1) Ethyl methyl amine (2) n-propylamine (3) Isopropylamine (4) Ethylamine

Q56.The hydration of propyne results in formation of (1) Acetone (2) Propanol-1 (3) Propene (4) Propanal