Properties
Define Acid and Alkali
Acid: A substance that ionize when it DISSOLVE IN WATER and IONIZES to HYDROGEN ION OR HYDROXIDE ION
Alkali: is a BASE that is DISSOLVE IN WATER and IONIZES to HYDROXIDE ION
pH=-log[H+]
pOH=-log[OH-]
pH+pOH=14
pOH=14-4.0
pOH=10
What completely ionizes in solution?
Strong acids and strong alkalis
What is the name for this compound?
HI
Hydroiodic acid
Which of the following is the base? Why do you say so?
A. Apple juice
B. Milk
C. Potassium Oxide
D. Soft drinks
Potassium Oxide because a base is a substance that react with water to form salt and water.
K2O + H2O → K+OH- + H2
Sulphuric acid has a [H+] of 1.7 x 10-2 M. Its pH is?
H2SO2 → H+ + HSO4-
pH=-log[H+]
pH= -log (1.7 x 10-2)
pH = 1.77
An acid that does not break apart completely.
Range from 4-7 on the pH scale.
What is me?
weak acid
What is the name for this compound?
H3PO4
Phosphoric acid
Which of the following is a diproctic acid?
A. Ethanoic Acid
B. Phosphoric acid
C. Sulphuric acid
D. Hydrochloric acid
sulphuric acid because it ionize 2 Hydrogen ions. it is a weak acid for the reaction is reversible
H2SO4 → H+ + HSO4-
HSO4- ⇄ H+ + HSO4-2
What is the pH of a solution with [H+]=1.24 x 10-2
pH=- log [H+]
pH= - log [1.24 x 10-2]
pH=1.91
Completely dissociates in water to form OH- ions.
Strong alkali
Write the chemical formula for nitrous acid
HNO2
When a neutral solution is tested using Methyl orange, what colour is formed?
Yellow
Why water is neutral?
Because water can ionizes the same number of moles of hydrogen ion and hydroxide ion.
What is type of acid that ionises completely in water to produce a high concentration of hydrogen ions, H+.
Strong acid
What is the name for this compound?
C2H2O4
Oxalic acid
Properties of alkali
1. bitter
2. pH value > 7
3. corrosive
4. slippery
Determine the molarity of lithium hydroxide solution LiOH with pH value 12.0
LiOH → Li+ + OH-
given the pH for hyroxide ion is 12.0, hence we need to find the the pOH for hydroxide ion.
pH + pOH = 14.0
12.0 + pOH = 14.0
pOH = 14.0-12.0
= 2.0
pOH = - log [OH-]
2.0 = - log [OH-]
log [OH-] = -2.0
[OH-] = 10-2
= 0.01 mol dm-3
Therefore, the molarity of LiOH = 0.01 mol dm-3
Ammonia and potassium hydroxide have same concentration, but why ammonia have a lower pH value?
Because ammonia...
is weak base that ionise partially in water to produce low concentration hydroxide ion
NH3 + H2O ⇄ NH4+ + OH-
KOH → K+ + OH-
Write the chemical formula for chlorous acid
HCIO2