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CHEMISTRY

CHEMISTRY. STOICHIOMETRY & COLLOIDS. The equivalent mass of MnSO 4 is half of its molecular mass when it is converted into- 1. Mn 2 O 3 2. KMnO 4 3. MnO 2 4. K 2 MnO 4. Answer : - 3 rd option Mn 2+ → Mn 4+. 1.98 g of Zn displaces 1.92 g of copper from

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CHEMISTRY

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  1. CHEMISTRY • STOICHIOMETRY & COLLOIDS

  2. The equivalent mass of MnSO4 is half of its molecular mass when it is converted into- • 1. Mn2O3 • 2. KMnO4 • 3. MnO2 • 4. K2MnO4 Answer : - 3rd option Mn2+ → Mn4+

  3. 1.98 g of Zn displaces 1.92 g of copper from • CuSo4 solution. So the Equivalent mass of Zinc • is : - (Equivalent Mass of Cu = 31.8) • 1. 32.79 • 2. 32.3 • 3. 65.5 • 4. 63.5 Answer :- Option No 1 E=32.79 1.98 = E 1.92 31.8

  4. The element whose atom has a mass of • 6.642 x 10 -26 Kg is – • 1. Silver • 2. Zinc • 3. Calcium • 4. Boron Answer:- Option No3 Atomic Mass = Mass of atom x N4 = 6.642x10-26 x 6.022x1023 = 0.040 kg = 40 g = at Mass of calcium = 40

  5. The number of molecules in 16 g of methane is • 3.0 x 1023 • 6.022x1023 • 16/6.022x 1023 • 16 • 3.0 x 1023 Answer : - Option No 2 6.022x1023

  6. 19.7 kg of gold was recovered from a smuggler. So • the number of atoms of gold recovered is • ( At . Mass of Au = 197) • 1. 100 • 2. 6.022x1023 • 3. 6.022x1024 • 4. 6.022x1025 Answer : - Option No4

  7. Assuming fully decomposed the volume of CO2 • released at STP when 9.85 g of BaCo3 will be • ( At Mass of Ba=137) • 1. 0.84L • 2. 2.24 L • 3. 4.06L • 4. 1.12L Answer : - Option no 4 Baco3→Bao+Co2 197g→22.4 L 9.85g→? – 9.85x 22.4 197 = 1.12L

  8. The Indicator used in titrating oxalic acid with • caustic soda solution is • 1. Methyl Orange • 2. Methyl Red • 3. phenolphthalein • 4. Diphenylamine Answer : - Option No 3

  9. If a Mixture containing 3 moles of Hydrogen and 1 mole of Nitrogen is converted completely into ammonia, the ratio of initial and final volumes at the same temperature and pressure would be • 1. 1:2 • 2. 2:1 • 3. 1:3 • 4. 3:1 Answer : - Option no 2 N2+3H2→2NH3 4: 2 or 2:1

  10. The Molarity of a solution containing 5g of NaoH in 250cm3 solution is • 0.5 • 0.1 • 3. 2 • 4. 1 Answer : - Option No1 M = mass/dm3 G.mol. Mass 20 = 0.5 40

  11. The volume of water to be added to 100cm3 of 0.5N H2 SO4 to get decinormal solution is – • 400cm3 • 2. 500cm3 • 450cm3 • 4. 100cm3 Answer : - Option no 1 N1V1 = N2V2 100x0.5 = V2 x0.1 i.e. V2=500cm3 Vol of water to be added 500-100= 400cm3

  12. 30g of Magnesium and 30g of oxygen are reacted and the residual mixture contains • 60g of Mg only • 2. 40g of MgO and 20g of O2 • 3. 45g of MgO and 15g of O2 • 4. 50g of MgO and 10g of O2 Answer : - Option number 4 2Mg +O2→2MgO 48g Mg reacts with 32g of O2 48g 32g 2x40g so that 30g Mg, 30x32 = 20g of O2 48 Mass of MgO = 30+20=50 Mass of unreacted O2 = 30 – 20=10

  13. 20 cm3 of 0.05N HCl and 35cm3 of 0.01N NaOH are • mixed. The resulting solution will be- • Be Neutral • 2. Be basic • 3. Turn phenolphthalein into pink • 4. Turn methyl orange red Answer : - Option number 4

  14. When a small amount of FeCl3 is added to a freshly • precipitated Fe(OH)3, a reddish brown colloidal • solution is obtained. This phenomenon is know as- • Dialysis • 2. Peptisation • 3. Protection • 4. Dissolution Answer : - Option number 2

  15. In the preparation of AgI solution, the excess of • potassium iodide solution is added to silver nitrate • solution. The colloidal solution will have • Positive charge • 2. Negative charge • 3. No charge • 4. Both positive and negative charge Answer : - Option No 2

  16. In a colloidal system , total number of phases • is/are • One • 2. Two • 3. Three • 4. Eight Answer : - Option number 2

  17. Colloidal particles carry some charge. This can be • show by • Electrophoresis • 2. Dialysis • 3. Tyndall effect • 4. Brownian Movement. Answer : - Option no 1

  18. A metallic oxide has formula MO, If the atomic • mass of the metal is 24. the Equivalent mass of the • metal is 1) 12. 2) 24. 3) 36. 4) 18. Answer : - Option No1

  19. One mole of H2SO4 in a dm3 forms 1) 2N Solution. 2) IN Solution. 3) 0.105N Solution. 4) 0.25N Solution. Answer : - Option No1

  20. The volume of 0.5N NaOH which neutralizes 6.3g of oxalic acid crystals? 1)100cm3. 2)20cm3. 3)200cm3. 4)400cm3. 0.5NxV/1000=6.3/63 Answer : - Option No3

  21. Surface tension of hydrophilic sols is? • 1) Lower than water. 2) Higher than water. • 3) Equal to water. 4) Higher or lower than • water. Answer : - Option No1

  22. Lyophillic sols are more stable than lyophobic sols because? • 1) The colloidal particles have positive charge. • 2) The colloidal particles have no charge. • 3) The colloidal particles are solvated. • 4) There is strong electrostatic repulsion. Answer : - Option No3

  23. Colloidal particles can be separated from those of particles of molecular dimensions by • 1) Dialysis. • 2) Coagulation • 3) Electrophoresis. • 4) pyrolysis. Answer : - Option No 1

  24. An example of micelle is 1) Sodium stearate. 2) Gold sol. 3) Nacl Solution. 4) Ruby Glass. Answer : - Option No1

  25. Gelatin is mostly used in making ice creams in order to 1) Prevent making of a colloid. 2) Stabilize the colloid and prevent crystallizations. 3) Develop a taste. 4) Enrich the aroma. Answer : - Option No 2

  26. Cloud bursts due to 1) Attraction towards the electrical charge on the earth. 2) Large amount of water present in the cloud. 3) Dense cloud present in the upper atmosphere. 4) Mutual discharge of oppositely charged clouds resulting in the coagulation. Answer : - Option No 4

  27. Gold numbers of Gelatin(I), Gum arabic (II), egg albumin (III) are 0.005,0.20 and 0.18 respectively. Arrange these in decreasing order of protective power. 1) I > II > III. 2) I > III > II. 3) II > III > I. 4) III > II > I. Answer : - Option No 2

  28. Which of the following least effective in causing flocculation of ferric hydroxide sol? 1) K4[Fe(CN)6] 2) Na2CrO4 3) KBr 4) Na2so4 Answer : - Option No 3

  29. The Method usually employed for the destruction of a colloidal sol is 1) Addition of electrolytes. 2) Diffusion through animal membrane. 3) Condensation 4) Dialysis. Answer : - Option No 1

  30. Butter is a colloid formed when 1) Fat is dispersed in water. 2) Water is dispersed in fat. 3) Fat globules are dispersed in water and milk. 4) Fat globules are dispersed in water and curds. Answer : - Option No 2

  31. If the dispersed phase is a liquid and the dispersed medium is solid, the colloid is known as a/an 1) Sol. 2) emulsion. 3) gel. 4) Foam. Answer : - Option No 3

  32. In case of small cuts, bleeding is stopped by applying potash alum, here alum acts as 1) Fungicide. 2) Disinfectant. 3) Germicide. 4) coagulating agent. Answer : - Option No 4

  33. The simplest way to check whether a system is colloidal is by 1) Tyndall effect. 2) Brownian movement. 3) Electro dialysis. 4) Finding out particle size. Answer : - Option No 1

  34. A liquid is found to scatter a light beam but leaves no residue on passing through the filter paper. 1) a suspension. 2) An oil. 3) a colloidal sol. 4) a true solution. Answer : - Option No 3

  35. Dialysis can separate 1) Glucose and Fructose. 2) Glucose and Sucrose. 3) Glucose and Nacl. 4) Glucose and protein. Answer : - Option No 4

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