What do you understand by the term ‘universal indicator’?
What do you understand by the term ‘universal indicator’?
Ans: – The indicator is nothing but the pH value of different object which tells us the nature of the substance is acidic or basic.
What is acid rain?
Ans: – Acid is the mixture of water and the toxic gas present in the air. It affects the monument or the marbles present in open area.
H2O + SO2 —-> H2SO4
What is the importance of pH for humans and animals, and our digestive system?
Ans: – He pH is very important for the digestion if the food present in our body as this food after the reaction with the basic substance which has more pH value than the minimise the acidity in our body.
Which chemical causes pain and burning sensation when somebody accidentally touches ‘nettle plant’?
Ans: – Histamine Acetylcholine is used for the pain and the burning sensation when somebody accidentally touches nettle plant.
What is a salt? Give two examples.
Ans: – The reaction between the acid and the bas in a reaction make the product salt and water.
Example: –
NaOH + HCl —-> NaCl + H2O.
How are salts obtained from an acid? Mention four types of substances that can be used for it.
Ans: – The reaction of acid with the basic substance makes the salt. For example, various acid or basic substance like NaOH, HC, MgO, CaO, NH4Cl etc.
Give chemical formula of (i) baking soda and (ii) washing soda.
Ans: – Baking soda: – NaHCO3.
Washing soda: – Na2CO3.
List the raw materials required for the manufacture of baking soda and describe the process with the help of suitable chemical equations.
Ans: –
The raw materials required to manufacture washing soda, Lime stone, Sodium chloride (NaCl) in the form of brine, Ammonia (NH3)
CaCO3(s) ⎯→ CaO(s) + CO2(g)↑
NaCl(aq) + CO2(g) + NH3(g) + H2O(l) ⎯→ NaHCO3(s)↓ + NH4Cl(aq)
2NaHCO3⎯⎯→ Na2CO3 + H2O + CO2↑
Distinguish between baking powder and baking soda. Why is baking powder preferred for making cakes?
Ans: – Baking powder is manufacturers by the uses of tartaric acid and the baking soda and baking soda is made from the reaction between ammonia, carbon dioxide, water.
2NaHCO3⎯⎯→ Na2CO3 + H2O + CO2↑
This cO2 emission makes the cake soft.
Give any two uses of baking soda.
Ans: – Baking soda is used for the making of bread, this also used for the making of baking powder.
What is washing soda? Give its chemical formula. How is it manufactured by Solvay’s method?
Ans: – Washing soda is used for the clearing of dust particles in clothes.
Chemical formula according to Solvay’s method,
2NaHCO3⎯→ Na2CO3 + H2O + CO2
Na2CO3 + 10H2O ⎯→ Na2CO3.10H2O.
Give two uses of washing soda.
Ans: – The uses of washing soda-
- As cleaning regent.
- Remove the hardness of water.
What is the chemical formula of ‘plaster of paris’? How is it manufactured? What precaution is taken during its manufacture?
Ans: – 2CaSO4.H2O or CaSO4.1/2H2O is the chemical formula of plaster of paris.
Manufacture of plaster of paris.
Raw material: –
Gypsum or CaSO4.2H2O
CaSO4.2H2O ⎯⎯⎯⎯⎯→ CaSO4.1/2H2O + 3/2H2O.
List any four uses of ‘plaster of paris’.
Ans: – Uses of plaster of paris: –
- For making of walls and ceiling smooth.
- For the decorative designs on ceilings, walls and pillars.
- For making ‘chalk’ for writing on blackboard.
- Making the fire proof materials.
What is bleaching? Chemically, what is bleaching powder? Give its any four uses.
Ans: – Bleaching powder is used for the disinfectant.
Its chemical name is calcium chloro hypochlorite.
Uses of bleaching powder is,
- Textile industry for bleaching of cotton and linen.
- paper industry for wood pulp bleaching.
- Make the wool unshrinkable.
- Used as disinfectant.
List the raw materials required and the method of manufacture of bleaching powder. Write the equation for the reaction involved.
Ans: – The raw material is, Slaked lime, Ca (OH)2 and Chlorine gas, Cl2.
Chemical reaction: – Ca (OH)2 + Cl2 ⎯→ CaOCl2 + H2O
- Follow on Facebook page – Click Here
- Google News join in – Click Here