This document is a student's PowerPoint presentation on acids and bases. It defines acids as substances that produce hydrogen ions in water, and bases as substances that produce hydroxide ions in water. It discusses the properties of acids and bases, including their tastes and how they feel. Common examples of acids and bases are provided. Indicators, pH, strong vs. weak acids and bases, and neutralization reactions are also explained.

1. *NAME- PIYUSH BHANDARI
*CLASS- ‘10’th
*SECTION- ‘A’*
*SUBJECT- SCIENCE P.P.T
*SUBMITTED TO- RAHUL GAUR

2. Chapter -2

3. Acids
 An acid is a substance that produces
hydrogen ions (H+
) when placed in water
When acids/ ionic compounds are dissolved in water,
the ions split apart from each other (dissociation)
Photo courtesy of:
http://www.biologycorner.com/worksheets/acids_bases_coloring.html

4. Properties of Acids
Most acids…
Taste sour
React w/many metals to form H2 gas
Are corrosive (appears to “eat away” materials
while reacting)
Have a chemical formula that begins with H
Photo Courtesy of:
http://healthmad.com/conditions-and-diseases/the-surprising-health-benefits-of-lemons/
Zinc Metal + Hydrochloric Acid  ??
Zn (s) + 2 HCl (aq) 
Predict the type of reaction based on the reactants!
Single-Displacement
H2 (g) + ZnCl2 (aq)

5. Common Acids
• Citric Acid
 Found in citrus fruits
• Used as a preservative
• Lactic Acid
 Found in yogurt
 Produced by our muscles when they are overworked
• Acetic Acid (HC2H3O2)
 Vinegar
 Used as a preservative
• Carbonic Acid ( H2CO3) or Phosphoric Acid (H3PO4)
 Found in soft drinks
• Hydrochloric Acid (HCl)
 Found in our stomachs- aids in food digestion
Photo Courtesy of:
http://stayinhealth.wordpress.com/2010/02/08/sugary-soft-drinks-increase-pancreas-cancer-risk

6. Bases
 A base is a substance that produces
hydroxide ions (OH-
) when placed in water
○ When bases/ ionic compounds are
dissolved in water, the ions split apart from
each other (dissociation)
Photo courtesy of:
http://www.biologycorner.com/worksheets/acids_bases_coloring.html

7. Properties of Bases
Most bases…
Taste bitter
Feel slippery
Are corrosive (appears to “eat away” materials
while reacting)
Have a chemical formula that ends with OH
Photo Courtesy Of:
http://www.pbs.org/wgbh/nova/body/bitter-taste.html

8. Common Bases
o Ammonia
• Cleaners and fertilizers
Sodium hydroxide
• Used in soaps and drain cleaners
Magnesium hydroxide
• An ingredient found in antacids

9. Indicators
 Indicators are used to determine if a substance is
an acid or a base
 An indicator changes a specific color when in the
presence of an acid or a base
 Litmus Paper: indicator made of a special filter paper
that contains dyes extracted from lichens (the crusty
“stuff” that grows in rocks)
Blue litmus turns red in an ACID
Red litmus turns blue in a BASE
Why do you think it’s important to test an
unknown substance with both types of litmus
paper?
If one type of litmus paper does not change color, that does not guarantee
that the other type of litmus paper will change color (i.e. water)

10. pH
 The pH scale can also help us classify
solutions as acids or bases
 pH is a measure of the amount of H+
ions in a solution (potential hydrogen)
The more H+
ions, the lower the pH, the
more acidic the solution

11. pH Scale
7 < pH ≤ 14

12. Complete the following chart by telling whether the pH
represents an acid, base or neutral substance.
Also tell what color each type of litmus paper will turn at
that pH level.
pH Acid/Base/Neutral Color of Blue Litmus Paper Color of Red Litmus Paper
2
8
4
7
13

13. Strength vs Concentration
 When describing acids and bases, strength and
concentration do not mean the same thing!
 Strength refers to the ability of the acid/base to
dissociate in solution
○ pH measures this
• Dissociation refers to the ability of an ionic compound to
break apart into ions
 Concentration refers to the amount of acid/base
dissolved in solution.
○ An acid or base will have the same pH, regardless of how
concentrated it is
• Just because you add water to dilute it, it’s still going to have the
same amount of H+
ions, they’ll just be spread out more

14. Strong/Weak Acids & Bases
 When a strong acid/base dissolves in
water, nearly all of the acid/base
molecules will dissociate into ions
 The greater the ability to dissociate, the
more potential the acid or base has for
being dangerous because there are more
ions available to react
 When a weak acid/base dissolves in
water, only a small fraction of the
acid/base molecules dissociate
(dissociate partially)
 With less ions in solution, there is less
potential for danger because there are
less ions available to react
Hydrogen
Hydrogen

15. Strong/Weak Acids Examples
 Strong Acids
1. HCl – hydrochloric acid – stomach
acid
2. H2SO4 – sulfuric acid – battery acid
3. HNO3 – nitric acid
 Weak Acids:
1. HC2H3O2 – acetic acid – vinegar
2. H3C6H5O7 –citric acid –citrus fruits

16. Strong/Weak Bases Examples
 Strong Bases:
1. NaOH – sodium hydroxide
2. Any alkali or alkaline earth metal with OH-
(i.e. KOH – potassium hydroxide)
 Weak Bases:
1. Al(OH)3 – aluminum hydroxide – often found in
deodorants
2. NH4OH – ammonium hydroxide (ammonia) –used in
many cleaning products

17. Neutralization
 Neutralization is a chemical reaction between an
acid and a base that takes place in a water solution
 When acids and bases react, the H+
ions from the
acid react with the OH-
ions from the base to form
HOH (H2O - water!)
 The overall pH becomes “neutral”
Many people that suffer from heartburn will take antacids to ease their
symptoms (i.e TUMS). How do you think antacids work?
The stomach is acidic due to HCl and antacids are basic.
A neutralization reaction occurs!

18. Salts
 The ions that are left behind after the H+
and OH-
ions form water, combine to form a salt
A salt is a compound that forms when the negative ions
from the acid combine with the positive ions from the
base
Acid + Base  Water + Salt
HCl(aq) + KOH(aq)  H2O(l) + KCl(aq)
What type of reaction is a neutralization reaction?
Double-Displacement
Name the salt produced in this neutralization reaction.
Potassium chloride