MCQs asked in CBSE 2010-2011
Q1: Out of the given four mixtures, the one that appears clear and transparent is:
(a) Chalk powder and water
(b) Sand and water
(c) Starch and water
(d) Sugar and water
Q2: The equipment required to prepare iron sulphide by heating a mixture of iron filings and sulphur powder is:
(b) Watch glass
Q3: On placing an iron nail in a copper sulphate solution, it is observed that:
(a) a soft and black coating is deposited on the iron nail.
(b) a reddish brown coating is deposited on the iron nail.
(c) a smooth and shiny coating is deposited on the iron nail.
(d) a grey and hard coating is deposited on the iron nail.
Q4: Rahul added 2 ml of Barium chloride solution to 2 ml sodium sulphate solution in a test tube and observed that:
(a) a clear solution was obtained
(b) two solutions formed separate layers ¡n the test tube
(c) the solution turned pink
(d) a white solid settled at the bottom
Q5: If common salt is added to the unsaturated solution of water and common salt it will
(a) become a colloid
(b) become a suspension
(c) start showing Tyndall effect
(d) remain a true solution
Q6: A student was asked to mix the white of an egg with water and stir well. The student observed that
(a) a transparent solution is formed.
(b) a translucent mixture is formed.
(c) egg white settles down at the bottom.
(d) egg white floats on the surface.
Q7: The reaction of iron and sulphur to form iron sulphide takes place at
(a) at high temperature
(b) in the presence of a catalyst
(c) at moderate temperature
(d) in the presence of an acid
Q8: Which of the following compounds when dissolved in water gives coloured solution ?
(a) barium chloride
(b) sugar solution
(c) sodium chloride
(d) copper sulphate
Q9: For determining the accurate melting point of ice we should prefer
(a) ice made from distilled water
(b) ice made from tap water
(c) crushed dry ice mixed with salt
(d) a mixture of ice and salt
Q10: Deepak was asked to prepare two samples of suspension by his teacher. When he went near the lab shelf he found the following substances.
(i) Fine sand (ii) Common salt (iii) Starch powder
(iv) Alum (v) Egg albumin (vi) Clay
Deepak should select :
(a) (i) and (ii)
(b) (i) and (vi)
(c) (ii) and (iii)
(d) (iv) and (v)
Q11: Which one of the following will result into the formation of compound of iron and sulphur?
(a) Mixing of iron filings and sulphur powder at room temperature.
(b) Adding iron filing to molten sulphur
(c) Heating the mixture of iron filing and sulphur powder
(d) Addition of carbon disulphide to a mixture of iron filings and sulphur powder
Q12: On burning magnesium ribbon a white ash is obtained which when dissolved in water turns a red litmus solution into blue. What is the name and nature of the white ash ?
(a) Magnesium hydroxide and basic in nature.
(b) Magnesium oxide and acidic in nature.
(c) Magnesium oxide and basic in nature.
(d) Magnesium chloride and acidic in nature.
Q13: Which of the following would you choose to determine the melting point of ice in your laboratory ?
(a) dry crushed ice
(b) ice cubes
(c) ice added to water
(d) slab of ice
Q14: A thermometer has 20 equal divisions between 90°C and 100°C marks. A student while determining the boiling point of water finds that the mercury thread becomes stationary at the 19th mark above 90°C. He should record the boiling point of water as :
Q15: The sequence commonly followed for separating a mixture of sand, common salt and ammonium chloride is :
(a) use of magnet, dissolving in water, filtration, sublimation
(b) dissolving in water, filtration, evaporation, sublimation
(c) sublimation, use of magnet, dissolving in water, filtration
(d) sublimation, dissolving in water, filtration, evaporation
Q16: Rema heated a mixture of iron filings and sulphur in a hard glass test tube for sometime till a greyish black product was formed. She cooled the test tube and added a few drops of carbon–di–sulphide and shook the contents well. The observation made by her was:
(a) the solution remain colourless
(b) the solution turns blue
(c) the solution turns pale green
(d) the solution turns yellow
Q17: While determining the boiling point of water, the teacher suggested to add some pumice stone pieces to the hard glass test tube containing water. This was done to:
(a) avoid bumping
(b) avoid melting of hard glass test tube
(c) prevent unnecessary loss of heat energy
(d) spread the heat uniformly.
Q18: Multinucleated condition is seen in
(a) only smooth muscle cells
(b) only skeletal muscle cells
(c) both smooth and skeletal muscle cells
(d) neither smooth nor skeletal muscle cells
Q19. Animal cells are commonly stained with
(a) methylene blue
(d) iodine solution
Q20. Deepak washed a few grains of tur dal in water. The water became yellow. He then added a few drops of HCl to the same test tube, the water turned pink in colour. From the above test Deepak concluded that tur dal contains.
(d) metanil yellow
Q21: Arun, Deepa, Uma and Priya were asked to select a plant material which would not give blue black colour with iodine solution. Who did not select the right material ?
(a) Arun selected maize grains.
(b) Deepa selected wheat grains.
(c) Uma selected ground nut seeds.
(d) Priya selected potato
Answer:1. (d) Sugar and water
2. (c) China-dish
3. (b) a reddish brown coating is deposited on the iron nail.
4. (d) a white solid settled at the bottom
5. (d) remain a true solution
6. (b) a translucent mixture is formed
7. (c) at moderate temperature
8. (d) copper sulphate
9. (a) ice made from distilled water (distilled water is pure water without impurities)
10. (b) (i) and (vi)
11. (c) Heating the mixture of iron filing and sulphur powder
12. (c) Magnesium oxide and basic in nature.
2Mg(s) + O2(g) ——> 2MgO(s)13 (a) dry crushed ice (dry crushed ice has larger surface area in touch with thermometer).
14 (b) 99.5°C
(Least count = (100-90)/20 = 0.5 i.e. each division represent 0.5°. Reading = 90° + 19x0.5 = 99.5°C)
15 (d) sublimation, dissolving in water, filtration, evaporation
16 (a) the solution remain colourless (Note: When it is a mixture of iron and sulphur, and then carbon-disulphide is added. Sulphur dissolves in Carbon-diSulphide making a yellow solution. In this question, IronSulphide is a compound here which will remain colourless with CS2. )
17 (a) avoid bumping
18 (b) only skeletal muscle cells
19. (a) methylene blue
20. (d) metanil yellow
21.(d) Priya selected potato (Note: Wheat, maize and ground nut seeds also contain starch. One need to crush them into powder before applying iodine test.)
Watch the You tube video pasted by ChemToddler showing reaction of Iron and Sulphur and formation of Iron Sulphide. The website ChemToodler is worth to visit.