Compounds Of Non-metals
Class 9th Chemistry Part Ii Kerala Board Solution
- Given below are the names of some chemicals. Sodium chloride, ammonium hydroxide, nitric…
- CaO is used as the drying agent while preparing ammonia in the laboratory. Can…
- Write down the property of sulphuric acid made use of, in the following situations? a)…
- Some salts, the chemicals used to identify them and the results of the experiments are…
- Two suggestions were made when there was a leak of ammonia gas. 1. Spray water 2. Spray…
Let Us Assess
Question 1.Given below are the names of some chemicals.
Sodium chloride, ammonium hydroxide, nitric acid, concentrated sulphuric acid, sodium hydroxide.
a) Select and write down the substances required to prepare hydrogen chloride.
b) Suggest a method to identify hydrogen chloride gas.
Answer:
a) When sodium chloride is heated with concentrated sulphuric acid then hydrogen chloride gas is produced.
NaCl + H2SO4→ NaHSO4 + HCl
b) Method to identify hydrogen chloride gas are:
•Moist gas turns blue litmus red.
•It has pungent (choking) smell.
•Bring a rod dipped in ammonia near the mouth of gas jar forms white smoke of ammonium chloride.
Question 2.
CaO is used as the drying agent while preparing ammonia in the laboratory. Can concentrated sulphuric acid be used as the drying agent in the place of CaO. Substantiate your answer.
Answer:
Calcium oxide (CaO) is used as drying agent while preparing ammonia but concentrated sulphuric acid cannot be used as drying agent because sulphuric acid is an acid and ammonia is basic they will react to form a salt (Ammonium sulphate). So, sulphuric acid cannot be used as drying agent.
Question 3.
Write down the property of sulphuric acid made use of, in the following situations?
a) During the preparation of chlorine gas, the gas is passed through concentrated sulphuric acid.
b) Wooden shelves get charred when they happen to come into contact with concentrated sulphuric acid.
Answer:
a) During the preparation of chlorine gas water are released so, sulphuric acid acts as an dehydrating agent which makes the moist chlorine gas dry.
b) Charring is the process in which the substance burns leaving behind the black spot. When the concentrated sulphuric acid falls on the wood it reacts with it till the colour of the wood turns black. This is called charring of wood.
Question 4.
Some salts, the chemicals used to identify them and the results of the experiments are arranged in an incorrect way in the table below. Match them and write in the correct order.
Answer:
Sulphate: - If barium chloride is added to a sample of water containing sulphate ions then barium sulphate is formed which is insoluble in water and white precipitate is observed.
e.g. Na2SO4 + BaCl2→ NaCl + BaSO4
Ammonium: - When Ammonium salt is mixed with the nessler’s reagent then it forms the precipitate of mercury (II) amido-iodide which gives the orange coloured precipitate.
Chloride: - When silver nitrate solution is added to a sample of water containing chloride ions then silver chloride is formed and white curdy precipitate is observed.
e.g. AgNO3 + NaCl → AgCl + NaNO3
Nitrate: - When ferrous sulphate and sulphuric acid is added to the sample of salt and if brown ring is observed in the test tube then it confirms the presence of nitrate ions.
Question 5.
Two suggestions were made when there was a leak of ammonia gas.
1. Spray water
2. Spray HCl
Which among this would you choose? Substantiate your answer.
Answer:
In the first case if we spray water on the ammonia gas, the ammonia gets dissolved in water and forms the hydroxide.
NH3 + H2O → NH4+ + OH-
In the second case if we spray HCl on ammonia gas white fumes will we released which to dangerous to the people around it.
NH3 + HCl → NH4Cl
So, if there is leak of ammonia gas water should be sprayed around it.
Extended Activities
Question 1.It is often said that the production of sulphuric acid is a bench mark of the industrial development of a country. Prepare a note based on the various uses of sulphuric acid.
Answer:
Sulphuric acid is very important industrial chemical. It is needed to manufacture many compounds and is used for many industrial processes. It is used in the production of fertilisers (super phosphate), used in petroleum refining, manufacturing of paints and pigments, used in detergent industries and also used for the storage batteries, metallurgical applications. Sulphuric acid is one of the main deciding factors of the growth of the country.
Question 2.
Collect more information about the industrial production and uses of strong acids like H2SO4, HCl, and HNO3. Prepare a note and present it in the class.
Answer:
HNO3: The major use of nitric acid is in the manufacture of ammonium nitrate for fertilisers and other nitrates for the use of explosives and pyrotechnics. It is also used in the preparation of nitro-glycerine and nitro organic compounds. Some of the other uses are pickling of stainless steel, etching of metals and oxidiser in rocket fuels.
H2SO4: It is used in the production of fertilisers (super phosphate), used in petroleum refining, manufacturing of paints and pigments, used in detergent industries and also used for the storage batteries, metallurgical applications.
HCl: It is used in manufacture of chlorine, NH4Cl and glucose, extracting glue from the bones. It is also used in medicine purposes and laboratory reagent.
Question 3.
Fill half of a beaker of capacity 50 mL with sugar. Add concentrated sulphuric acid so that the sugar is immersed in it. Observe the changes. What are the products formed? Which property of sulphuric acid is revealed here?
Answer:
Sugar is a carbohydrate, so when we add sugar to sulphuric acid the water from the molecule gets dehydrated and we have only elemental carbon.
C12H22O11 + H2SO4→ 12 C + 11 H2O + mixture water and acid
The reaction is exothermic, much of the water is boiled off as steam.
This called as the charring of sugar.