Title RACE-PHYSICAL CHEMISTRY 2022-23.pdf ✅

TARGET : PRE-MEDICAL 2023 PHYSICAL CHEMISTRY SOME BASIC CONCEPT OF CHEMISTRY (MOLE CONCEPT) 1. The volume of a gas at 00C and 760 mm pressure is 22.4 cc. The no. of molecules present in this volume is (1) 10–3 NA (2) 10–4 NA (3) 10–5 NA (4) 10–2 NA 2. 100 mL of PH3 when completely decomposed produces phosphorus and hydrogen. The change in volume of the gas is - PH3 (g) o P(s) + 3 2 H2 (g) (1) 50 mL increase (2) 500 mL decrease (3) 900 mL decrease (4) Does not changes 3. The mass of a molecule of water : (1) 30 × 10–24 kg (2) 3 × 10–26 kg (3) 1.5 × 10–26 kg (4) 2.5 × 10–27 kg 4. 19.7 kg of gold was recovered from a smuggler. How many atoms of gold were recovered ? (At. wt. of gold (Au) = 197) (1) 100 (2) 6.023 × 1023 (3) 6.023 × 1024 (4) 6.023 × 1025 5. Chlorine is prepared in the laboratory by treating manganese dioxide (MnO2 ) with aqueous hydrochloric acid according to the reaction 4HCl(aq) + MnO2 (s) o 2H2O( A) + MnCl2 (aq) + Cl2 (g) How many gram of HCl react with 5.0 g of manganese dioxide ? (At. wt. of Mn = 55) (1) 2.12 g (2) 44.24 g (3) 8.4 g (4) 3.65 g 6. An unknown amino acid has 0.032% sulphur by wt. If each molecule has one S atom only, 1 g. of amino acid has ........... molecules :- (1) 6.02 × 1018 (2) 6.02 × 1019 (3) 6.02 × 1024 (4) 6.02 × 1023 7. 446 g of PbO, 46 g of NO2 and 16 g of O2 are allowed to react according to the equation :- PbO + 2NO2 + 1 2 O2 o Pb(NO3 ) 2 The amount of Pb(NO3 ) 2 that can be produced is (At. wt. of Pb = 207) :- (1) 331 g (2) 662 g (3) 165.5 g (4) 132.5 g 8. 44g of a sample of organic compound on complete combustion gives 88g CO2 and 36g of H2O. The molecular formula of the compound may be :- (1) C4H6 (2) C2H6O (3) C2H4O (4) C3H6O 9. Volume at N.T.P. of 0.22 g of CO2 is same as that of (1) 0.01 g of hydrogen (2) 0.085 g of NH3 (3) 320 mg of gaseous SO2 (4) All the above 10. Which of the following has maximum mass :- (1) 0.1 gram atom of carbon (2) 0.1 mol of ammonia (3) 6.02 × 1022 molecules of hydrogen (4) 1120 cc of carbon dioxide at STP 11. What mass of NaCl would be decomposed by 98 g of H2 SO4 if 120 g of NaHSO4 and 27.5 g of HCl are produced in a reaction. Assuming that law of mass conservation is true: (1) 4.95 g (2) 49.5 g (3) 0.495 g (4) 495 g 12. Equal mass of oxgyen, hydrogen and methane are taken in a container in identical conditions. What is the ratio of their moles :- (1) 1 : 16 : 1 (2) 1 : 16 : 2 (3) 8 : 1 : 8 (4) 16 : 1 : 8 13. When 40 cc of slightly moist hydrogen chloride gas is mixed with 20 cc of ammonia gas the final volume; of gas left at the same temperature and pressure will be NH3 (g) + HCl(g) o NH4Cl(s) (1) 20 cc (2) 40 cc (3) 60 cc (4) 100 cc 14. Which of the following has greatest number of atoms :- (1) 1g of butane (C4H10) (2) 1 g of nitrogen (N2 ) (3) 1 g of silver (Ag) (4) 1 g of water (H2O) N O A H ••
TARGET : PRE-MEDICAL 2023 PHYSICAL CHEMISTRY 15. One atom of an element 'X' weighs 6.664 × 10–23 g. The number of gram atoms in 40 kg of it is (1) 10 (2) 100 (3) 10000 (4) 1000 16. In the reaction, 4A + 2B + 3C oA4B2C3 , what will be the number of moles of product formed, starting from 1 mol of A, 0.6 mol of B and 0.72 mol of C :- (1) 0.25 (2) 0.3 (3) 0.24 (4) 2.32 17. If Ca3 (PO4 ) 2 and H3 PO3 contain same number of 'P' atom then the ratio of oxygen atoms in these compounds respectively is :- (1) 8/3 (2) 2/3 (3) 3 (4) 4/3 18. Calculate the number of oxygen atoms required to combine with 7g of N2 to form N2O3 when 80% of N2 is converted into N2O3 :- (1) 2.3 × 1023 (2) 3.6 × 1023 (3) 1.8 × 1021 (4) 5.4 × 1021 19. Element X reacts with oxygen to produce a pure sample of X2O3 . In an experiment it is found that 1.00 g of X produces 1.16 g of X2O3 . Calculate the atomic weight of X :- (1) 67 (2) 100.2 (3) 125 (4) 150 20. In a compound A containing carbon, hydrogen and oxygen, the % of hydrogen is one sixth that of carbon which is 1.5 times that of oxygen. What is the simplest formula for the compound:- (1) C2H4O2 (2) C2H4O (3) C2H6O (4) CH4O Que. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Ans 112431334422114 Que. 16 17 18 19 20 21 22 23 24 25 Ans 3424212332 ANSWER KEY 21. 1 mole of Fe2 S3 , 2 moles of H2O and 3 moles of O2 are allowed to react according to the equation [2Fe2 S3 (s) + 6H2O(A) + 3O2 (g)o4Fe(OH)3 (s) + 6S(s)] The number of moles of Fe(OH)3 (s) that can be produced is :- (1) 1.34 (2) 2 (3) 4 (4) 3 22. A gaseous alkane was burnt with oxygen. The volume of O2 for complete combustion and that of CO2 formed are in the ratio of 7 : 4. The molecular formula of alkane is :- (1) CH4 (2) C2H6 (3) C3H8 (4) C4H10 23. Two oxides of a metal contain 22.22% and 30% oxygen by mass respectively. If the formula of the first oxide is MO, then the formula of the second oxide is :- (1) MO (2) MO2 (3) M2O3 (4) M2O 24. Caffeine has a molecular weight of 194. If it contains 29% by mass of nitrogen, number of atoms of nitrogen in one molecule of caffeine is :- (1) 2 (2) 6 (3) 4 (4) 3 25. Sulphur trioxide is prepared by the following two reactions. S8 (s) + 8O2 (g) o 8SO2 (g) 2SO2 (g) + O2 (g) o 2SO3 (g) How many grams of SO3 are produced from 1 mol of S8 ? (1) 1280.0 (2) 640.0 (3) 960.0 (4) 320.0 N O A H ••
TARGET : PRE-MEDICAL 2023 PHYSICAL CHEMISTRY ATOMIC STRUCTURE 1. Energy required for the process is : He+ (g) oHe+2(g) + e– The ionisation energy for the H-atom in the ground state is 2.18 × 10–18 J atom–1 (1) 9.12 × 10–18 J (2) 8.72 × 10–18 J (3) 4.72 × 10–20 J (4) 7.82 × 10–16 J 2. The difference between nth and (n + 1)th Bohr orbits' radii of H atom is equal to its (n – 1)th Bohr orbit's radius. The value of n is :- (1) 1 (2) 2 (3) 3 (4) 4 3. When an electron of mass 6m and charge 6e moves with a velocity of 7v about the nuclear charge Ze in a circular orbit of radius 'r'. The potential energy of the electron will be :- (1) 2 Ze r (2) 2 Ze r (3) 2 6Ze r (4) S 2 4 2 2 2 2 me Z n h 4. Be+3 and a proton are accelerated by the same potential, their de-Broglie wavelengths have the ratio : (Assume mass of proton = mass of neutron) (1) 1 : 2 (2) 1 : 4 (3) 1 : 1 (4) 1 : 3 3 5. A single electron in an ion has ionisation energy equal to 217.6 eV. What is the total number of neutrons present in that ion is :- (1) 2 (2) 4 (3) 5 (4) 9 6. The number of photons emitted in 10 hours by a 60 W sodium lamp (O = 5893 Å) will be :- (1) 1.6 × 1024 (2) 3.2 × 1024 (3) 6.4 × 1024 (4) 8 × 1023 7. The distance between 3rd and 2nd orbit of hydrogen atom :- (1) 2.646 × 10–8 cm (2) 2.116 × 10–8 cm (3) 1.058 × 10–8 cm (4) 0.529 × 10–8 cm 8. How fast is an electron moving if it has a wavelength equal to the distance it travels in one second ? (1) h m (2) m h (3) h P (4) h 2(KE) 9. Hydrogen atoms are excited to n = 4 state, in the spectrum of emitted radiation, number of lines in the ultravoilet and visible regions are respectively :- (1) 3, 1 (2) 1, 3 (3) 2, 3 (4) 3, 2 10. Which oribital notation does not have spherical node :- (1) n = 2, A = 0 (2) n = 3, A = 1 (3) n = 3, A = 0 (4) n = 1, A = 0 11. The difference in angular momentum associated with the electron in two successive orbits of hydrogen atom is :- (1) h S (2) h 2S (3) h 2 (4) (n–1) h 2S 12. If uncertainties in the measurement of position and momentum are equal, uncertainty in the measurement of velocity. (1) 1 h m S (2) 1 h 2m S (3) h S (4) None of these 13. Find out the number of waves made by a Bohr electron in one complete revolution in its fourth orbit. (1) 3 (2) 4 (3) 2 (4) 1