DPP-15 to 16 With Answer Physical Chemistry

FACULTY COPY DAILY PRACTICE PROBLEMS (DPP) Subject : Physical/Inorg.Chemistry Date : DPP No. 15 Class : XIII Course : DPP No.1 Max. Time : 31 Total Time : 31 min. Single choice Objective ('–1' negative marking) Q.1 to Q.9 (3 marks 3 min.) [27, 27] Subjective Questions ('–1' negative marking) Q.10 (4 marks 4 min.) [4, 4] 1. Equivalent weight of NH3 in the change N2  NH3 is : (1) 17/6 (2) 17 (3) 17/2 (4*) 17/3 2. A sample of 1.0 g of calcite (pure CaCO3) required 39.5 mL of HCl complete reaction. Calculate the normality of the acid. (1) 0.41 N (2) 0.61 N (3*) 0.51 N (4) 0.15 N 3. Number of moles of electrons taken up when 1 mole of NO  ions is reduced to 1 mole of NH OH is : (1) 2 (2) 4 (3) 5 (4*) 6 4. In the following reaction hydrazine is oxidized to N2. N H + OH–  N + H O + e The equivalent weight of N2H4 (hydrazine) is (1*) 8 (2) 16 (3) 32 (4) 64 5. Which of the following sets of quantum numbers can be correct for an electron in 4f-orbitals ? (1) n = 3, 𝑙 = 2, m = –2, s = + 1 (2) n = 4, 𝑙 = 4, m = –4, s = – 1 2 2 (3*) n = 4, 𝑙 = 3, m = +1, s = + 1 (4) n = 4, 𝑙 = 3, m = +4, s = + 1 2 2 Sol. For n = 4, 𝑙  4, for 𝑙 = 3, m  4 (n = 4, 𝑙  4, for 𝑙 = 3, m  4 ds fy,½ 6. In the following electronic configuration, some rules have been violated : I : Hund II : Pauli's exclusion III : Aufbau (1) I and II (2) I and III (3) II and III (4*) I, II and III 7. In the electronic configuration of Mn(Z = 25) : (1) the number of electrons having n + 𝑙 = 4 are 5 (2*) the number of electrons having m = 0 are 13 (3) the magnetic moment is 1.73 BM (4) Mn belongs to IIIrd period and d-Block in periodic table. Sol. Mn - 1s2 2s2 2p6 3s2 3p6 3d5 4s2 m = 0 for all s-electron and two-p electron and one d-electron hence total = 13. 8. A wavelength of 400 nm of electro magnetic radiation of corresponds to : (1) frequency () = 7.5 × 1014 Hz (2) wave number(  ) = 2.5 × 106 m–1. (3) momentum (m) = 1.66 × 10–27 kg ms–1 (4*) all are correct values. Sol. Use C =   u  1  9. The total volume of 0.1 M KMnO4 solution that are needed to oxidize 144 mg of ferrous oxalate and 152 mg of ferrous sulphate in a mixture in acidic medium is : (1) 5 mL (2) 2 mL (3*) 8 mL (4) None of these Sol. m-eq. of KMnO4 = m.eq. of FeC2O4 + m-eq. of FeSO4 (0.1 × 5) × V = 144 144 3 152 + 152 ; 1 V = 8 mL 10. Calculate ratio of wavelength for an proton and -particle if they are accelerated through same potential V : Ans. p  2 2  1 Sol. Use  = FACULTY COPY DAILY PRACTICE PROBLEMS (DPP) Subject : Physical/Inorg.Chemistry Date : DPP No. 16 Class : XIII Course : DPP No.2 Max. Marks : 30 Total Time : 30 min. Single choice Objective ('–1' negative marking) Q.1 to Q.10 (3 marks 3 min.) [30, 30] 1. Alveoli are the tiny sacs of air in the lungs whose average diameter is 50 pm. Consider an oxygen molecule trapped within a sac. Calculate uncertainty in the velocity of oxygen molecule ? (1) 1.98 × 10–2 ms–1 (2*) 19.8 ms–1 (3) 198 × 10–4 ms–1 (4) 19.8 × 10–6ms–1 Sol. x = 50 pm So v = h 4.mx 6.625  10 34  6.022  1023 = 4  3.14  32  103  50  1012 m/sec = 0.0019853 × 104 m/sec = 19.853 m/sec. 2. Magnetic moment of 25Mnx is B.M then the value of x is : (1) 1 (2) 2 (3) 3 (4*) 4 Sol. 25Mn – [Ar] 3d54s2 Given = 15  n = 3 Hence to have ‘3’ unpaired electrons Mn must be in ‘+4’ state. 3. The maximum number of electrons in s, p and d-subshells are : (1) 2 in each (2) 2, 6 and 6 (3*) 2, 6 and 10 (4) 2, 6 and 12 4. In the reaction 2CuSO + 4K  Cu  +  + 2K SO the equivalent weight of CuSO4 will be (atomic weight of Cu = 63.5) 5. The equivalent weight of a metal is double than of oxygen. How many times is the weight of it’s oxide greater than the weight of the metal ? (1*) 1.5 (2) 2 (3) 3 (4) 4 6. A 10-volume H2O2 solution is equal to (1) 3% (w/v) H2O2 (2) 30 g/L H2O2 (3) 1.76 N (4*) all of these mijksDr lHkh 7. 4 mole of a mixture of Mohr’s salt and Fe2(SO4)3 requires 500 mL 1M K2Cr2O7 for complete oxidation in acidic medium. The mole % of the Mohr’s salt in the mixture is : (1) 25 (2) 50 (3) 60 (4*) 75 Sol. Cr O 2– + 6Fe2+ (n = 1) (Mohr’s salt) + 14H+  2Cr3+ + 6Fe3+ + 7H O 2 7 2 Equivalent of Fe2+ = moles of Mohr’s salt = equivalent of K2Cr2O7 = 500 × 10–3 × 6 × 1 = 3.0 Hence, mole percent of Mohr’s salt = 3 × 100 = 75 4 8. Which one is the correct order of the size of the iodine species (1) I > I+ > I– (2) I > I– > I+ (3) I+ > I– > I (4*) I– > I > I+ 9. Radii of fluorine and neon in angstrom units are respectively given by (1*) 0.762, 1.60 (2) 1.60, 1.60 (3) 0.72, 0.72 (4) None of these values (1*) 0.762, 1.60 (2) 1.60, 1.60 (3) 0.72, 0.72 (4)buesalsdksbZekuugha Sol. Nobel gases have largest radii in the periodic table. 10. X2+ is isoelectronic of sulphur and has (Z + 2) neutrons (Z is atomic no. of X2+). Hence mass number of X2+ is : (1) 34 (2) 36 (3*) 38 (4) 40