Practice Questions

Q51. The electron in the nth orbit of Li2 + is excited to ( n + 1 ) orbit using the radiation of energy 1 . 47 × 10-17 J (as shown in the diagram). The value of n is ___________ Given : RH = 2 . 18 × 10-18 J

Q51.Among following compounds, the number of those present in copper matte is A. CuCO3 B. Cu2 S C. Cu2 O D. FeO

Q51.In chromyl chloride, the number of d-electrons present on chromium is same as in (Given at no. of Ti : 22, V : 23, Cr : 24, Mn : 25, Fe : 26 ) (1) V (IV) (2) Mn (VII) (3) Fe (III) (4) Ti (III)

Q51.A solution of sugar is obtained by mixing 200 g of its 25% solution and 500 g of its 40 % solution (both by mass). The mass percentage of the resulting sugar solution is _______ (Nearest integer) JEE Main 2023 (11 Apr Shift 1) JEE Main Previous Year Paper

Q51.On complete combustion, 0 . 492 g of an organic compound gave 0 . 792 g of CO2. The % of carbon in the organic compound is (Nearest integer)

Q51.The energy of one mole of photons of radiation of frequency 2 × 1012 Hz in Jmol-1 is _____ . (Nearest integer) (Given: h = 6 . 626 × 10-34Js NA = 6 . 022 × 1023 mol-1)

Q51.If wavelength of the first line of the Paschen series of hydrogen atom is 720 nm, then the wavelength of the second line of this series is _______ nm. (Nearest integer)

Q51.The density of 3M solution of NaCl is 1 . 0 g mL-1. Molality of the solution is ______ × 10-2 m (Nearest integer). Given: Molar mass of Na and Cl is 23 and 35 . 5 g mol-1 respectively.

Q51.In Hall-Heroult process, the following is used for reducing Al2 O3 :- (1) Magnesium (2) Na3 AlF6 (3) Graphite (4) CaF2

Q51.Formulae for Nessler's reagent is: (1) KHg2 I2 (2) KHgI3 (3) K2 HgI4 (4) HgI2

Q51.The number of bent-shaped molecule/s from the following is ______ N3- , NO2- , I3- , O3, SO2

Q51.If 5 moles of BaCl2 is mixed with 2 moles of Na3PO4, the maximum number of moles of Ba3PO42formed is _________ (Nearest integer)

Q51.The total number of isoelectronic species from the given set is ________. O2−, F–, Al, Mg2+, Na+, O+, Mg, Al3+, F Q52. 30. 4 kJ of heat is required to melt one mole of sodium chloride and the entropy change at the melting point is 28. 4 J K–1 mol–1 at 1 atm. The melting point of sodium chloride is _______ K (Nearest Integer)

Q51.The incorrect statement from the following for borazine is: (1) It contains banana bonds (2) It can react with water (3) It is a cyclic compound (4) It has electronic delocalization

Q51.Which one of the following statements is incorrect ? (1) van Arkel method is used to purify tungsten. (2) The malleable iron is prepared from cast iron by oxidising impurities in a reverberatory furnace. (3) Cast iron is obtained by melting pig iron with (4) Boron and Indium can be purified by zone scrap iron and coke using hot air blast. refining method.

Q51.Potassium dichromate acts as a strong oxidizing agent in acidic solution. During this process, the oxidation state changes from (1) +3 to +1 (2) +6 to +3 (3) +2 to +1 (4) +6 to +2

Q52.Correct order of spin only magnetic moment of the following complex ions is: (Given At. No. Fe : 26, Co : 27 ) (1) [FeF6]3−> [CoF6]3−> [Co (C2O4)3]3− (2) [Co (C2O4)3]3−> [CoF6]3−> [FeF6]3− (3) [FeF6]3−> [Co (C2O4)3]3−> [CoF6]3− (4) [CoF6]3−> [FeF6]3−> [Co (C2O4)3]3−

Q52. KMnO4 oxidises I− in acidic and neutral/faintly alkaline solution, respectively to (1) I2 and IO−3 (2) IO−3 and I2 (3) IO−3 and IO−3 (4) I2 and I2

Q52.Zinc reacts with hydrochloric acid to give hydrogen and zinc chloride. The volume of hydrogen gas produced at STP from the reaction of 11 . 5 g of zinc with excess HCl is L (Nearest integer) (Given : Molar mass of Zn is 65 . 4 g mol-1 and Molar volume of H2 at STP = 22 . 7 L )

Q52.The orbital angular momentum of an electron in 3 s orbital is 2π.xh The value of Q53.20 mL of 0 . 1MNaOH is added to 50 mL of 0 . 1M acetic acid solution. The pH of the resulting solution is × 10-2. (Nearest integer) Given : pK𝑎CH3COOH = 4 . 76 log 2 = 0 . 30 log 3 = 0 . 48

Q52.The sum of lone pairs present on the central atom of the interhalogen IF5 and IF7 is ______

Q52.The pair of lanthanides in which both elements have high third-ionization energy is: (1) Dy, Gd (2) Lu, Yb (3) Eu, Yb (4) Eu, Gd

Q52.How many of the following metal ions have similar value of spin only magnetic moment in gaseous state? ________ (Given: Atomic number : V, 23; Cr, 24; Fe, 26; Ni, 28) V3+, Cr3+, Fe2+, Ni3+

Q52.The ratio of sigma and π bonds present in pyrophosphoric acid is

Q52.The incorrect statement regarding the reaction given below is (1) The product ‘ B’ formed in the above reaction is p (2) ‘ B’ is N-nitroso ammonium compound -nitroso compound at low temperature (3) The reaction occurs at low temperature (4) The electrophile involved in the reaction is NO+ JEE Main 2023 (12 Apr Shift 1) JEE Main Previous Year Paper