plant and animal cell class 8

EXPERIMENT 5

EXPERIMENT-4

AIM
To study the following properties of acetic acid (ethanoic acid):

1. Odour
2. Solubility in water
3. Effect on litmus
4. Reaction with sodium bicarbonate

MATERIALS REQUIRED
Acetic acid, litmus paper, sodium bicarbonate, test tubes, water, test tube stand, lime water.

THEORY

1. Acetic acid is an organic acid and its 5-8% solution is called vinegar.
2. It is a weak acid. It ionises partially.
   
3. It turns blue litmus red.
4. It is highly soluble in water.
5. It reacts with sodium bicarbonate to liberate CO2 which turns lime water milky and the milkiness disappears if excess of CO2 is passed through the solution.
   

PROCEDURE, OBSERVATIONS AND INFERENCE

RESULT

1. Acetic acid/ethanoic acid (CH3COOH) has a pungent smell like vinegar.
2. Acetic acid is miscible in water in all proportions i.e. acetic acid and water form a true solution.
3. Acetic acid is acidic in nature as it turns blue litmus red.
4. On reaction with sodium bicarbonate, CO2 gas is liberated.

PRECAUTIONS

1. Do not inhale vapours of pure acetic acid directly.
2. Keep the mouth of the test tube away from you and your classmates.
3. Freshly prepared lime water should be used.

EXPERIMENT -3
AIM- TO STUDY PROPERTIES OF ACIDS AND BASES

Aim(a) To study the properties of acids (HCl) by their reaction with

1. Litmus solution(Blue/Red)
2. Zinc metal(Zn)
3. Solid sodium carbonate(Na2COs).

Materials RequiredTest tubes, test tube stand, test tube holder, cork, droppers, beaker, litmus (red and blue), Zn metal granules, solid sodium carbonate, dil. HCl.

Theory

1. HCl is an acid. Acids turn blue litmus red and do not affect red litmus.
2. On reacting with zinc metal, it forms a salt, zinc chloride (ZnCl2) and hydrogen gas (H2) is liberated.
   Zn(s) + 2HCl(aq) → ZnCl2(aq) +H2↑
   Hydrogen gas burns in air with a pop sound.
   2H2(g) + O2(g) → 2H20(l)
3. HCl reacts with sodium carbonate (aqueous/solid) to liberate carbon dioxide(CO2) which turns lime water milky. When excess of CO2 is passed through the solution, the milkiness disappears.
   

Procedure And Observation Table

Result

1. HCI turns blue litmus red.
2. It releases H2 gas on reaction with Zn metal.
3. It liberates C02 gas on reaction with Na2C03.

Precautions

1. HCI is corrosive, therefore, handle it with care.
2. Use small quantities of chemicals.
3. A fine jet should be taken for burning hydrogen.
4. Use clean zinc metal, otherwise the reaction will occur very slowly.
5. Wash your hands properly with soap after the experiment.

Aim

(b) To study the properties of bases(NaOH) by their reaction with

1. Litmus solution(Blue/Red)
2. Zinc metal(Zn)
3. Solid sodium carbonate(Na2CO3)

Materials RequiredDil. NaOH, test tubes, test tube holder, test tube stand, red and blue litmus solutions, zinc metal, sodium carbonate and droppers.
Theory

1. NaOH is a base. Bases turn red litmus blue and do not affect blue litmus.
2. On reacting with zinc metal, NaOH forms sodium zincate and hydrogen gas is liberated. The hydrogen gas burns with a pop sound.
   
3. NaOH does not react with solid or aqueous Na2CO3.

Procedure And Observation Table

Result

1. NaOH turns red litmus blue.
2. On reaction with Zn metal, it releases H2
3. It does not react with Na2COg.

Precautions

1. Handle NaOH with care.
2. Use small quantities of chemicals.
3. A fine jet should be taken for burning hydrogen.
4. Zn granules should be clean.
5. Wash your hands properly after completing experiment.

DEAR CHILDREN
FOR LESSON NOTES OF CARBON AND ITS COMPOUNDS TYPE LESSON NOTES-CARBON AND ITS COMPOUNDS.IT WILL APPEAR IN THE PREVIOUS YEARS BLOG

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