Tuesday, February 18, 2014

ICSE Chemistry -2014 Important Questions

Chemistry Objective questions for ICSE -2014
A.      State one observation in each of the following-
1.       Excess of ammonium hydroxide is added to copper sulphate solution.
2.       Silver nitrate solution is added to HCl
3.       Conc. Sulphuric acid is added to Copper sulphate crystals.
4.       Moist red litmus is brought near the mouth of test tube containing ammonia gas.
5.       Moist blue litmus paper is brought  near the mouth of test tube containing HCl gas.
6.       Nitric oxide gas is passed though freshly prepared ferrous sulphate solution.
7.       Solution of Barium chloride and Solver nitrate are added.
8.       Ethyne is bubbled through Bromine dissolved in Carbon tetra chloride.
9.       Zinc is added to dil sulphuric acid.
10.    Zinc granules are added to conc. Nitric acid.
11.    Zinc Carbonate is heated in a test tube and the test tube is left to cool.
12.    Sodium carbonate solution is added to solution of CaCl2
13.    Oxygen and nitric oxide are mixed and the product is shaken with distilled water.
14.    Water is added to the product obtained by burning magnesium is air and the gas thus produced is brought in contact with HCl gas.
15.    H2S gas is passed through Bromine water.
16.    Copper nitrate crystals are heated.
17.    Aluminium carbide is reacted with water and the gas thus produced is burnt in deficient air supply.
18.    Acetylene is bubbled through ammonical cuprous chloride solution.
19.    Ammonium hydroxide solution is added to lead nitrate solution first slowly and then in excess.
20.    Ammonium sulphate is heated with caustic soda and the gas thus produces is bubbled through methyl orange solution.
21.    Copper is heated with conc. Nitric acid and the the gas thus produced is passed into KI solution.
22.    Iron (II) sulphide is heated with dil sulphuric acid and the gas thus evolved is passed through lead acetate solution.
23.    Trilead tetraoxide is heated with cocn HCl.
24.    Conc. Nitric acid is added to methanol.
25.    Dil. Sulphuric acid is added to lead nitrate solution.
26.    Ammonia gas is passed through a solution obtained by reactic copper (II) oxide and dilute sulphuric acid.
27.    Solutions of sodium chloride and sodium hydroxide are mixed.
28.    Barium nitrate is added to potassium carbonate solution.
29.    Sodium nitrate, copper and cocn. Sulphuric acid are added.
30.    Con. Sulphuric acid is added to ethanol and the gas thus evolved is passed through bromine dissolved in carbon tetra chloride.

B.      Give reasons why-
1.       Copper can conduct electricity but S cannot.
2.       Hydrogen chloride gas fumes in air.
3.       Bottles containing NaOH are not covered using glass stoppers.
4.       Hydrochloric acid is used for pickling of metals before galvanizing.
5.       Hydrogen chloride gas is never collected over water
6.       Addition of con sulphuric acid to zinc liberates sulphur dioxide gas but dilute acid liberate hydrogen.
7.       Aluminium oxide is not reduced by reducing agents.
8.       In the laboratory ammonia is collected by downward displacement of air.
9.       In haber’s process for manufacturing of ammonia external heating is not required once the process starts.
10.    In contact process, the gases passing through the oxidation chamber should be free from arsenic impurities.
11.    In laboratory preparation of methane NAOH is always used with CaO.
12.    In laboratory preparation of HCl the temperature is always kept below 200oC
13.    In laboratory preparation of nitric acid the temperature is always kept below 200oC.
14.    In preparation of sulfuric acid through contact process SO3 gas is never added directly to water.
15.    Con. HCl is never used for preparation of HNO3.
16.    For dilution of sulphuric acid, acid is always added to water with constant stirring.
17.    Dry SO2 can’t bleach a rose petal.
18.    For electroplating the article to be electroplated is always made cathode.
19.    For electroplating of Ag, silver nitrate is never used.
20.    Nitric acid is always stored in dark bottles.

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