to study the properties of acids and bases HCl and NaOH by their reaction with
litmus solution (blue/red)
zinc metal
solid sodium carbonate
Answers
Acids will turn blue litmus red
Acids react with zinc to form Hydrogen gas
As zinc is amphoteric therefore it reacts with a base
Acids react with sodium carbonate to form metal carbonate and h2 gas
Basic Building Concepts
Acids are sour in taste while bases are bitter in taste.
When an acid reacts with a metal, hydrogen gas is evolved and a corresponding salt is formed.
When a base reacts with a metal, along with the evolution of hydrogen gas a salt is formed which has a negative ion composed of metal and oxygen.
When an acid reacts with a metal carbonate, it gives the corresponding salt, carbon dioxide gas and water.
Bases do not react with metal carbonate.
Aim
(a) To study the properties of acids (HCl) by their reaction with
Litmus solution(Blue/Red)
Zinc metal(Zn)
Solid sodium carbonate(Na2COs).
Materials Required
Test tubes, test tube stand, test tube holder, cork, droppers, beaker, litmus (red and blue), Zn metal granules, solid sodium carbonate, dil. HCl.
Theory
HCl is an acid. Acids turn blue litmus red and do not affect red litmus.
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)
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.
Result
HCI turns blue litmus red.
It releases H2 gas on reaction with Zn metal.
It liberates C02 gas on reaction with Na2C03.
Precautions
HCI is corrosive, therefore, handle it with care.
Use small quantities of chemicals.
A fine jet should be taken for burning hydrogen.
Use clean zinc metal, otherwise the reaction will occur very slowly.
Wash your hands properly with soap after the experiment.
Aim
(b) To study the properties of bases(NaOH) by their reaction with
Litmus solution(Blue/Red)
Zinc metal(Zn)
Solid sodium carbonate(Na2CO3)
Materials Required
Dil. NaOH, test tubes, test tube holder, test tube stand, red and blue litmus solutions, zinc metal, sodium carbonate and droppers.
Theory
NaOH is a base. Bases turn red litmus blue and do not affect blue litmus.
On reacting with zinc metal, NaOH forms sodium zincate and hydrogen gas is liberated. The hydrogen gas burns with a pop sound.
NaOH does not react with solid or aqueous Na2CO3.
Procedure And Observation Table
cbse-class-10-science-practical-skills-properties-of-acids-and-bases-4
Result
NaOH turns red litmus blue.
On reaction with Zn metal, it releases H2
It does not react with Na2COg.
Precautions
Handle NaOH with care.
Use small quantities of chemicals.
A fine jet should be taken for burning hydrogen.
Zn granules should be clean.
Wash your hands properly after completing experiment.