This document discusses the reactivity of acids and bases. It explains that when a metal reacts with an acid, hydrogen gas is released and a salt is formed. Specific reactions of zinc and magnesium with hydrochloric acid are given as examples. The document also discusses the reaction of acids with metal oxides and carbonates, forming salts and water. A short quiz is included at the end to test understanding of acid-base reactions.

1. GOOD
MORNING

3. SCIENCE AND TECHNOLOGY
CHAPTER FIVE
Acids, bases and salts
REACTIVITY OF ACIDS
CLASS IX
State board

4. Reactivity of acids and
bases
Neutralisatio
n
Reaction of
acids with
metals
Reaction of acids
with oxides of
metals
Reaction of
bases with oxides
of non-metals
Reaction of acids
with carbonate and
bicarbonate of
metals

6. When metal reacts with an acid, hydrogen gas
is released.
𝒁𝒏(𝒔) + 𝟐𝑯𝑪𝑳(𝒂𝒒)  Zn𝑪𝑳𝟐(𝒂𝒒) + 𝑯𝟐(𝒈) ↑
Zinc + Hydrochloric acid  Zinc chloride + Hydrogen gas
Metal + Acid  Salt + Hydrogen

7. When metal reacts with an acid, hydrogen gas
is released.
𝒁𝒏(𝒔) + 𝑯𝟐𝑺𝑶𝟒(𝒂𝒒)  Zn𝑺𝑶𝟒(𝒂𝒒) + 𝑯𝟐(𝒈) ↑
Zinc + Sulphuric acid  Zinc sulphate + Hydrogen gas
Metal + Acid  Salt + Hydrogen

8. Reaction of acids with metal
 Reaction of acids with metals depends upon the
strength and concentration of the acid and also on
the reactivity of the metal and the temperature.
 For example: dilute acids react easily with
moderately reactive metals at normal
temperature.

10. The reactive metal displaces hydrogen from
the acid and releases hydrogen gas.
𝑴𝒈(𝒔) + 𝟐𝑯𝑪𝑳(𝒂𝒒)  Mg𝑪𝑳𝟐(𝒂𝒒) + 𝑯𝟐(𝒈) ↑
Magnesium + Hydrochloric acid  Magnesium chloride + Hydrogen gas
Metal + Acid  Salt + Hydrogen gas

13. Reaction of acids with oxides of metals
𝑭𝒆𝟐𝑶𝟑(𝒔) + 𝟔𝑯𝑪𝑳(𝒂𝒒)  2Fe𝑪𝑳𝟑(𝒂𝒒) + 𝟑𝑯𝟐𝑶(𝒍)
Iron(III)oxide + Hydrochloric acid  Ferric chloride + Water
Metal Oxide + Acid  Salt + Water

15. The gas which burns with a ‘pop’ sound is
• Carbon dioxide
• Hydrogen
• Nitrogen
• Oxygen
Explanation
Hydrogen is a flammable gas which burns with a pop
sound.

16. A gas ‘X’ is evolved when a metal reacts with a dilute acid.
Can you name the gas?
Hint: The gas burns with a pop sound.

17. Explanation
• Metals react with dilute acids to produce metal salts
and hydrogen gas
• Hence, the gas ‘X’ would be hydrogen which burns
with a pop sound.
Metal + Acid  Salt + Hydrogen gas

18. 1. Which one of the following is acidic?
(a) Lemon juice
(b) Tomatoes
(c) Milk
(d) All
Ans. (d) All
2. Metal Oxide + Acid  Salt + ______
Ans. Water
3. Metal + Acid  Salt + ________
Ans. Hydrogen gas

19. Lets Play
Quizizz