CHEMISTRY-27-08- 11th (J-Batch) WA

REVIEW TEST-2 Class : XI (J-Batch) Time : 100 min Max. Marks : 75 General Remarks: INSTRUCTIONS 1. The question paper contain 14 questions and 20 pages. All questions are compulsory. Please ensure that the Question Paper you have received contains all the QUESTIONS and Pages. If you found some mistake like missing questions or pages then contact immediately to the Invigilator. 2. Each question should be done only in the space provided for it, otherwise the solution will not be checked. 3. Use of Calculator, Log table and Mobile is not permitted. 4. Legibility and clarity in answering the question will be appreciated. 5. Put a cross ( × ) on the rough work done by you. Name Father's Name Class : Batch : B.C. Roll No. Invigilator's Full Name USEFUL DATA Atomic weights: Al = 27, Mg = 24, Cu = 63.5, Mn = 55, Cl = 35.5, O = 16, H = 1, P = 31, Ag = 108, N = 14, Li = 7, I = 127, Cr = 52, K=39, S = 32, Na = 23, C = 12, Br = 80, Fe = 56, Ca = 40, Zn = 65.4, Pt = 195, He = 4, Ba = 137. R = 8.31 J/(mol - K) = 0.082 lt - atm/(mol - K) For Office Use ……………………………. Total Marks Obtained………………… Q.No 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Marks Q.1 Two vessels connected by a valve of negligible volume. One container (I) has 2.8 g of N2 & 12.7 g of I2 at temperature T1 (K). The other container (II) is completely evacuated. The container (I) is heated to T2 (K) while container (II) is maintained at T2/3 (K). The valve is opened. Calculate masses of N2 in both containers after a very long time. I2 sublimes at T2 (K) and volume of vessel (I) is half that of vessel (II). Neglect vapour pressure of I2 (s). [4] Q.2 H2O2 + 2KI 40%yield I2 + 2KOH H2O2 + 2KMnO4 + 3H2SO4 50%yieldK2SO4 + 2MnSO4 + 3O2 + 4H2O 100 ml of H2O2 sample was divided into two parts. First part was treated with KI and KOH formed required 200 ml of M/2 H2SO4 for neutralisation. Other part was treated with KMnO4 yielding 6.74 lit. of O2 at STP. Using % yield indicated find volume strength of H2O2 sample used. [4] Q.3 Rate of diffusion of ozonized oxygen is 0.4 5 times that of pure oxygen. Find (a) Percentage by mass of ozone in the ozonized sample (b) Degree of dissociation of oxygen assuming pure O2 in the sample initially. [2+2] Q.4 An open vessel at 27°C is heated. Assuming that volume of vessel remains constant. Calculate (a) Temperature to which vessel was heated till (3/5)th of air in it has been expelled. (b) Fraction of molecules escaped out when vessel is heated to 900 K (c) Temperature at which half of the air escapes out. [1.5+1.5+1] Q.5 Heat released when 1 mole of acid HX neutralizes 1 mol of base BOH is M 30 KJ. To a solution containing HX of molarity 10 another solution containing base BOH was slowly added. Aplot between heat liberated (J) and volume of BOH (ml) added was obtained as shown. (a) Calculate molarity of base. (b) Calculate volume of original HX solution [2.5+2.5] Q.6 200 g of an oleum sample was dissolved in excess water. To this solution 1 kg of impure Ba(NO3)2 was added causing formation of BaSO4 precipitate. The precipitate formed was filtered, washed & dried. Its weight was 582.5 gm. Find % labelling of oleum sample. [5] Q.7 400 ml of 0.2 × 10–3 M Ca(NO3)2 solution is mixed with 400 ml of 10–4 M NaHCO3 solution. If density of resulting solution is 1 g/ml. Calculate (a) ppm of Ca(HCO3)2 in final solution (b) Molality of Na+ in solution (c) Molarity of Ca2+ in solution [2+2+1] Q.8 A bulb of constant volume is attached to a manometer tube open at other end as shown in figure. The manometer is filled with a liquid of density (1/3)rd that of mercury. Initially h was 228 cm. Through a small hole in the bulb dp gas leaked causing pressure decrease as dt = – kP. If value of h is 114 cm after 7 minutes. Calculate value of k in units of hour–1. [Use: ln (4/3) = 0.28 & density of Hg = 13.6 g/ml] [5] Q.9 Calculate minimum number of balloons each of volume 82 lit. required to lift a mass of 1 kg to a height of 831 m. Given: molar mass of air = 29 g/mol, temperature is constant at 290 K and mass of each balloon is 50 g. [Use e–0.1 = 0.9, pressure at sea level = 1 atm, acceleration due to gravity (g) = 10 m/s2] [5] Q.10 A mixture 1,2–Dipropene and hydrogen gas was placed in a rigid steel container at a constant temperature of 18°C. Initial pressure of mixture was 10 atm. Sparking the mixture caused hydrogenation reaction C3H4 (g) + 2H2(g)  C3H8 (g) causing pressure to decrease by 6 atm. Excess O2 was then added and on sparking the pressure further decreased by 11 atm. Calculate decrease in pressure by treating final mixture with aqueous KOH solution. [6] Q.11 0.2 gm of an anhydrous organic acid gave on combustion 0.04 g water and 0.195 g of CO2. 0.5 g of its silver salt leaves on ignition 0.355 g silver. In another experiment 100 ml of 0.2 M acid solution was 1 neutralised by 400 ml of 10 M caustic potash solution. What is molecular formula of acid? [6] Q.12 1.8 g of MBrx (M is a metal) when heated with a stream of HCl gas was completely converted to chloride MClx which weighed 1 g. Specific heat of metal is 0.11 cal/g. Calculate percent error in molecular weight of metal bromide as determined from specific heat data. [Use: Atomic weight of metal × specific heat = 6.4] [7] Q.13 A tube of uniform cross-section of 0.5 cm2 and length 118 cm is divided into three compartments by using two frictionless pistons each of mass 101.32 gm. The compartments I, II & III are filled by equal masses of CH4, O2 and He gases respectively as shown. The tube is then inverted at angle of 30° with horizontal as shown. If pressure in CH4 compartment was 1 atm find volumes of compartments I, II and III. Assume volume of piston is negligible and temperature is constant. [Use g = 10 m/s2 and 1 atm = 1.0132 × 105 Pa] [7] Q.14 A vessel of volume 246 lit. contains 1.8 g of water and N2 gas at a total pressure of 0.41 atm. If half the contents of vessel are transferred to another evacuated vessel of volume 24.6 lit. Calculate (a) Final total pressure in both vessels (b) Relative humidityin both vessels. [Assume constant temperature of 300 K. Aqueous tension of water is 15.2 mmHg. ] [4+4]

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