CHEMISTRY-15-10- 11th (PQRS) Code-A

XI (PQRS) CHEMISTRY REVIEW TEST-5 Select the correct alternative. (Only one is correct) [15 × 3 = 45] There is NEGATIVE marking. 1 mark will be deducted for each wrong answer. Q.16 For a general atom A having three different existance A, A–, A+1, Mark the correct option. (A) Size order will be A+ > A– > A (B*) E A order will be A+ > A > A– (C) I E order will be A > A– > A+ (D) E N order will be A– > A > A+ Q.17 Alarge number of oil drop samples in Milikan’s oil drop experiment gave the following values of charges q = 2×10–19 coulomb, 3×10–18 coulomb, 4 ×10–19 coulomb, 5 ×10–18 coulomb & no other values. What could be concluded as the charge of e– from above information. (A) 2 × 10–18 coulomb (B*) 2 × 10–19 coulomb (C) 1 × 10–19 coulomb (D) 5 × 10–20 coulomb [Sol. least value present & all other are multiples of least value ] Q.18 Certain amount of phosphorus (P4) was made to react with certain amount of oxygen to give a mixture of P4O6 & P4O10 in the molar ratio of 2 : 1 (P4O6 : P4O10). If none of the reactants remained after the reaction(s) then what was the ratio of mass of P4 : O2 taken initially. (A*) 93 : 88 (B) 88 : 93 (C) 3 : 11 (D) 11 : 3 Q.19 For a closed (not rigid) container containing n = 10 moles of an ideal gas, fitted with movable, frictionless, weightless piston operating such that pressure of gas remains constant at 0.821 atm, which graph represents correct variation of log V vs log T where V is in lit. & T in Kelvin. (A*) (B) (C) (D) [Sol. Q P & n constant  PV = nRT  V = nR T P  log V = log nR P + log T  log V = ln 1 + ln T  log V = log T  y = x  (A) ] Q.20 Calculate total maximum mass (kg) which can be lifted by 10 identical balloon (each having volume 82.1 lit. and mass of material = 3 kg) at a height 83.14 m at Mars where g = 5 m/s2 & atmosphere contains only Ar (At. wt.40). At Mars temperature is 10 K and density of atmosphere at ground level is 2 k gm/lit. [Given : e–0.1 = 0.9] (Assume d 0.821 H = d0 eMgh RT to be applicable). (A*) 2000 × 0.81–30 (B) 1970 (C) 2000 × 0.9 –30 (D) 2000 × 0.81 – 3 Q.21 Consider the following nuclear reactions involving X & Y. X  Y + 4 He Y  8O18 + 1H1 If both neutrons as well as protons in both the sides are conserved in nuclear reaction then identify period number of X & moles of neutrons in 4.6 gm of X (A) 3, 2.4 NA (B*) 3, 2.4 (C) 2, 4.6 (D) 3, 0.2 NA Q.22 40 miligram diatomic volatile substance (X2) is converted to vapour that displaced 4.92 ml of air at 1 atm & 300 K. Atomic weight of element X is (A) 400 (B) 40 (C) 200 (D*) 100 Q.23 Electromagnetic radiations having  = 310 Å are subjected to a metal sheet having work function = 12.8 eV. What will be the velocity of photoelectrons with maximum Kinetic Energy.. (A) 0, no emission will occur (B) 2.18 × 106 m/s (C) 2.18 × 106 m/s (D*) 8.72 × 106 m/s Q.24 An U tube containing ideal gas closed at both ends having infinite long columns consists of mercury having initial height difference of 76 cm as shown. Both left column & right column have a hole from which gas is coming out according to rate law as given. [Assume outside the U-tube to be a perfect vaccum at all the instant] Given: ln2 = 0.69 Left Column dP = K P ; K = 0.693 × 10–2 sec–1 dt 1 1 dP Right Column = K P ; K = 1.386 × 10–2 sec–1 dt 2 2 where P = Pressure in the respective column If at t = 0 pressure in Left Column = 1atm then what will be the height difference in the two levels after 200 sec. (A*) 0 (B) 76 (C) 38 (D) 19 Q.25 A very long rectangular box is divided into n equal compartments with (n–1) fixed SPM (semi permeable membrane) numbered from 1 to (n–1) [n is unknown] as shown. The gases are initially present in only I compartment & can pass through only those SPM whose number is less than or equal to their subscript (like A1 can pass through 1st SPM only, A2 through 1st & 2nd & so on). If initially all gases have same moles & after substantial time ratio of P in 3rd compartment to P in 1st compartment is 5 then what 6 n1 would be the value of n (where PA6 & PAn1 represents partial pressure of A6 & An1 respectively) is (A) 10 (B) 15 (C*) 35 (D) 30 [Sol. From the info it can be concluded, after substantial time. A1 is present in I & II comp. A2 is present in I, II & III comp.  A6 in I, II VIII & An–1 in all compartment & Q V & T same P 6 P n1 n 6 = n n1 (3rd) (1st) a = 7  a n = 5 n =35 ] Q.26 A mixture of CH4 (15 ml), CO (10 ml) is mixed with sufficient O2 gas in an eudiometry tube(operating at 1 atm & 500 K) is subjected to sparking and then cooled back to the original temperature of 500K. If Vc1 be volume contraction due to the above process and Vc2 be the contraction after passing the resultant gas(es) through CuSO4 (anhydrous), then Vc1,Vc2 will be (A) 30, 0 (B) 30, 30 (C*) 5, 30 (D) 5, 0 Q.27 If in Bohr’s model, for unielectronic atom, time period of revolution is represented as Tn,z where n represents shell no. and z represents atomic number then the value of T1,2 : T2,1 will be (A) 8 : 1 (B) 1 : 8 (C) 1 : 1 (D*) None of these Q.28 Assuming Heisenberg Uncertainity Principle to be true what could be the minimumuncertaintyin de-broglie wavelength of a moving electron accelerated by Potential Difference of 6 V whose uncertainty in position 7 is 22 n.m. (A) 6.25 Å (B) 6 Å (C*) 0.625 Å (D) 0.3125 Å [Sol. D.B. = Å = 5Å h h & x. p  4 P =  h  x. 2 ×   h  P = h  4 2 1 109  × 2 1 ×  > 4    2.5 4 × 10–10   0.625 Å ] Questions No. 29 to 30 (2 questions) Read the following comprehension and answer the question that follow. One of the concerns of various chemists is of selecting an appropriate equation of state which can relate the four parameters (P, V, T and n) & give results close to experimental values at critical conditions. Although Vander Waal equation is easy to use, the experimental value of 'Z' (compressibility factor) at critical condition does not match with the predicted value [Experimental :  0.27, Predicted (Vander Waal)  0.375] For this reason, another equation of state is being used known as  RT  a V RT Dieterici Equation P =   e m  V  b   m  where a, b are dieterici constant, Vm = Molar volume, P = Pressure & T = Temperature which gives better results at Critical Condition. ( ZCritical Condition = 2/e2).  dP   d2P  Also at Critical condition   = 0 &  2  = 0.  dV T   T If PC, VC, TC are critical pressure, volume & temperature and V & T are related as 2a × (V –b)2 = V3RT . C C C C C Q.29 PC, VC, TC in terms of dieterici constant will be respectively (A*) a 4b2e2 , 2b, a 4bR (B) a 27b2 , 3b, 8a 27 Rb (C) a 4b2e2 , 3b, a 4bR (D) a b2e2 , 2b, a 4bR Q.30 If Vr = V (reduced volume), Tr = C T P (reduced temperature) & Pr = C C (reduced pressure) then which of the following represents reduced equation of state for dieterici equation. [All equation dimensionally correct]  2  2    VrTr  1  e Tr V T e2T (A*) Pr e  Vr   =   2 (B) Pr e r r (Vr – b) = r 2 2a  1  e2T 2  1  e2T T (C) P e VrTr V   = r (D) P e VrTr V   = r C r  r 2  2 r  r 2  2 Select the correct alternative. (One or more than one is/are correct) [3 × 5 = 15] Q.49 Following represents the Maxwell distribution curve for an ideal gas at two temperatures T1 & T2. Which of the following option(s) are true? (A*) Total area under the two curves is independent of moles of gas (B*) If dU1= f Umps1 & dU2 = f Umps2 then A1 = A2 (C) T1 > T2 and hence higher the temperature, sharper the curve. (D*) The fraction of molecules having speed = Umps decreases as temperature increases. [Sol. A : Q area under the curve gives fraction of molecules & hence total area =1 B : From expression of Maxwell distribution fraction of molecules between Umps  Umps + f Umps is independent of value of Umps & is dependent only on f. C : T2 is higher temperature D : As seen from graph  A, B, D ] Q.50 In the following six electronic configuration (remaining inner orbitals are completely filled). Mark the correct option(s). C–I C–II C–III C–IV C–V C–VI (A*) Stability order : C–II > C–I & C–IV > C–III (B*) Order of spin multiplicity : C–IV > C–III = C–I > C–II (C*) C–V violates all the three rules of electronic configuration (D) If C–VI represents Athen A2+ when kept near a magnet faces weak repulsions (acts as dimagnetic). [Sol. A : excitation possible onlt in d-orbitals B : Spin multiplicity = 2 | S | + 1 ; | S | = total spin  the order C : C–V; Pauli’s violated , Hunds violated & Aufban violated D : A+2 has two unpaired  paramagnetic  A, B, C are correct ] Q.51 A sample of H2O2 solution labelled as 33.6 volume has density of 264 gm/lit. Mark the correct option(s) representing concentration of same solution in other units.[Solution contains only H2O & H2O2] (A*) Mole fraction of H2O2 in the solution = 0.25 (B) % w/v = 102% (C) MH O = 6 M (D*) 1000 m 2 2 = 54 m [Sol. Vstrength = 33.6  M = 3M  1l  3 molesof H2O2 l = 264 gm/lit. 1l = 264 g  H2O (wt.) = 162 gm H2O(n) = 9 H2O2 = 3  XH O = 3 12 = 0.25 102 1000 ×100 = 10.2 % 3 & m = 162 × 1000 1000 = 54  options (A) & (D) ] MATCH THE COLUMN [2 × 8 = 16] INSTRUCTIONS: Column-I and column-II contains four entries each. Entries of column-I are to be matched with some entries of column-II. One or more than one entries of column-I mayhave the matching with the same entries of column-II and one entryof column-I mayhave one or more than one matching with entries of column-II. Q.3 For any chemical reaction Reactants  products; the net energy change involved in the process is Eproducts – Ereactants . Using this & the following ENERGY diagram representing energy of each collection. Match column I with column II. Column I (Process) Column II | Energy change | (A) EA1 of Mg+(g) (P) 25 (B) IE1of Cl– (g) (Q) 100 (C) H.E. of Mg+2 (g) (R) 350 (D) L.E. of MgCl2(s) (S) 400 [Ans. (A) Q (B) P (C) R (D) S] Q.4 Column I & column II contain data on Schrondinger Wave–M echanical model, where symbols have their usual meanings.M atch thecolumns. Column I Column II (Type of orbital) (A) (P) 4s (B) (Q) 5px (C) (, ) = K (independent of  & ) (R) 3s (D) atleast one angular node is present (S) 6dxy [Ans. (A) P, (B) P,Q,S, (C) P, R (D) Q, S] [Sol. (A) s orbital Q r = 0 ,   0 & 3 radial nodes  4s  A  D (B) 3 radial nodes (s,p,d) anything  4s, 5px, 6dxy (C) Q angular probability independent of   3s, 4s (D) Atleast angular node  5px (1) 6dxy (2) ]