Fill in the blanks:
- The acid found in lemon is Citric acid.
- The bases have a Bitter taste and Soapy touch.
- The sitting of the Ant containers formic acid.
- Sulphuric acid is a highly Corrosive acid.
- Acidic soils are neutralize with Slaked lime
[ II ]The statements given below are incorrect write correct statements. - 1. Sulphuric acid is an example of an organic acid
- Answer: Sulphuric acid is an example of mineral acid
- 2. Blue litmus paper turns red in the basic solution
Answer: Blue litmus paper turns red in acidic solution
3. China rose solution turns green in citric acid solutions
Answer: China rose solution turns green in basic solutions
4. Formic acid is found in the sitting of a grasshopper
Answer: Formic acid is found in the sting of an ant
5. During neutralization an acid reacts with a salt to form water and a base as products
Answer: During neutralization an acid reacts with a base to form salt and water as productus
Write true or false infront of the following sentences
1. False
2. True
3. True
4. False
5. False
6. True
Answer the following questions:
Q.1 Name three organic and inorganic acids.
Answer: Organic acids: citric acid tartaric acid lactic acid acetic acid
In organic acids: sulphuric acid nitric acid hydrochloric acid phosphoric acid
Q2. What are the indicators name any three indicators and state the colour change which takes place in (i) acids(ii) bases.
Answer: The substances date change dear colour on coming in contact with acid or base are called indicators for example turmeric litmus solution China rose and petals
Litmus changes to red when added to an acidic solution
Phenolphthalein changes to Deep pink colour when added to the base solution.
Q3. What are neutral substances give examples of two neutral substances.
Answer: Neutral substances are those substances that are neither acidic or basic for example alcohol distilled water common salt.
Q4. You are given three unlabeled bottle is a b and c containing colourless solution is such that one of them is acidic The other being basic and neutral how will you distinguish between them by using China rose is an indicator.
Answer: If the colour of China rose changes to green colour we can say that the solution in the bottle is base if it is colour changes to Deep pink colour than the solution in the water is acidic and if no change takes place in the bottle we can say the solution in the bottle is neutral
Q5. What do you understand by the term neutralisation describe an activity in which neutralisation of hydrochloric acid takes place with sodium hydroxide using phenolphthalein an indicator
Answer: The process due to which an acid completely reacts with a base with the evolution of heat to form salt and water is the only product is is called neutralization.
Q6. Explain why
[A] Farmers add slaked lime to acidic soils
Answer: In order to convert the acidic soil into neutral soil so that to increase its fertility for better crop yield
[B] Soap solution or baking soda paste is applied on the part of the body stung by a bee
Answer: When a baby sitting is it inject is formic acid into our body to reduce the effect of this acid soap solution or baking soda solution is applied around the affected area so it neutralizes the effect of the acid.
[C] Factory wastes and city severage is neutralizer before discharging in rivers
Answer: To prevent the killing of aquatic animal is factory waste is are neutralized before this charging in rivers because these wastes contain acid as and if directly discharge in rivers mein kill fishes and other living organisms .
[D] Antacids are used for relieving stomach activity
Answer; Sometimes when we eat more spicy food stomach was more hydrochloric acid causing acidity in the stomach to relieve this acidity antacids are used.
Q7. Give four differences between acids and alkalis
Answer:
Acid:
They have a sour taste
They turn blue litmus solution to red
They turn China rose solution to Deep pink colour
Most of the acids are soluble in water
Alkali or base:
They have a bitter taste.
They turn red litmus solution blue.
They turn China rose solution green.
Most of the bases are insoluble in water.
Q8. Write an equation when hydrochloric acid neutralizes sodium hydroxide
Answer: Equation of neutralization of HCL and NaOH is given below
HCL +NaOH..,……NaCL+H2O +Heat
