CURA, DARREL LOIS L.
September 22, 2023
BSN – 1
1. What is an Acid?
ACID is an acronym that stands for Atomicity, Consistency, Isolation, and Durability. It's a
set of properties that ensure that database transactions are processed reliably, even in the
face of software errors, hardware failures, or unexpected power outages. The Atomicity
property ensures that a transaction is treated as a single, indivisible unit of work. Either all of
the changes made in the transaction are committed to the database, or none of them are.
The Consistency property ensures that a transaction brings the database from one valid
state to another. The database must satisfy a set of integrity constraints before and after the
transaction is executed. The Isolation property ensures that the changes made by one
transaction are not visible to other transactions until the first transaction is committed. This
prevents conflicts and inconsistencies from arising. The Durability property ensures that the
changes made by a transaction are permanent, and that they survive any subsequent
failures or restarts of the database system. This is usually achieved by writing the changes
to non-volatile storage, such as disk.
Acids in solution have a pH below 7.0, a sour taste, releases hydroxyl ions in water, and turn
litmus paper red. Acids are divided into two main classes:

Strong acids are very corrosive and because severe skin burns, examples are
hydrochloric acid, nitric acid, and sulfuric acid. Also called mineral or inorganic acids.

Weak acids are mildly corrosive and normally do not affect skin, examples are acetic
acid (vinegar), citric acid (citrus fruit juice acid), and tartaric acid (used in making
mayonnaise). Also called natural or organic acids.
3 theories to call anything an acid
Arhenius theory
Acid is that compound which can donate H+ ion in water.
Eg NaOH is arhenius base
HCL is arhenius acid
Bronsted Lowry concept
Acid is acid anything which can donate H+ ion when dissolved in water and base is something
which can accept H+ ion.
Eg. H2SO4 —-> H+ +HSO4HSO4- —-> H+ +SO4HSO4- + H+ —-> H2SO4
Here HSO4- can act as bronsted acid as well as base.
Lewis concept
Acid is something which can accept an electron pair.
Eg. Alcl3, BF3.
Let’s classify H2O
H2O can give H+as well as OH- do it's arhenius acid as well as baseH2O can accept and
donate H+ ion so it's both bronsted base and acid. But due to presence of lone pair electrons on
oxygen of water molecule it can only Donate electron, that's why it's a Lewis Base.
2. What is pH?
Many people are aware that pH has something to do with acids or bases and that it is important
for things like water quality, food-making, aquatic life and plants, but not many really understand
what it means.
In simplest terms, a pH value indicates how acidic or basic water is. A pH of 7 indicates a
neutral solution, a pH greater than 7 indicates a basic solution, and a pH of less than 7 indicates
an acidic solution. The farther a pH value is from 7, the more strongly acidic or basic it is. For
example, water with a pH of 6 is mildly acidic, and water with a pH of 3 is highly acidic.
If you are satisfied with this answer, you can stop reading here. But if you want to know what pH
really means, read on…
So, what does pH really mean?
The ‘H’ in pH is the elemental symbol for hydrogen. The ‘p’ can refer to different things in
different languages, but the ‘pH’ is most commonly said to mean ‘power of hydrogen’.
So what does this mean?
The hydrogen referred to in the pH symbol is actually the hydrogen ion, which is written as H+.
A hydrogen atom has one proton (which has a positive charge) and one electron (which has a
negative charge). The hydrogen ion is a hydrogen atom that has given up its electron. Because
there is no longer a negative charge from the electron to balance the positive charge from the
proton, H+ has a net positive charge (hence the ‘+’ in the symbol).
Technical note: Sometimes the hydrogen ion is written as the hydronium ion (H3O+).
The presence of H+ is what makes water acidic. An acid is a compound that contributes H+ to
water, either directly or indirectly. For example, hydrochloric acid (HCl) dissociates into the
hydrogen (H+) and chloride (Cl-) ions in water, and it is the H+ that contributes to the acidity of
the water. The higher the concentration of H+, the more acidic the water is.
HCl ® H+ + Cl-
The concentration of H+ can be expressed in terms of moles per liter of water (one mole is
6.022×1023 objects, also known as Avogadro’s number). The value of pH reflects the
concentration of H+ as follows:
(concentration of H+ in mol/L) = 10-pH
For example, at pH 6, the concentration of H+ is 10-6 or 0.000001 mol/L. At pH 3, the
concentration is 10-3 or 0.001 mol/L.
Technical note: Professional chemists may use slightly different definitions of pH that account
for the non-ideal behavior of the hydrogen ion or that use different concentration units (such as
moles per kg of (water)
but the above relationship explains the meaning of pH well enough for many people.
What about neutral and basic solutions?
Water molecules break apart into two ions, the hydrogen ion (H+) and hydroxyl ion (OH-):
H2O = H+ + OHThis reaction is reversible, so that H+ and OH- can recombine to form water molecules. At any
given time, the concentrations of H+ and OH- are very small compared to the amount of water
molecules.
It happens that at pH 7, the concentrations of H+ and OH- are equal. This is why pH 7 is
considered the neutral pH. Below pH 7, the concentration of H+ is greater than the
concentration of OH-, making the water acidic. Above pH 7, the concentration of OH- is greater
than the concentration of H+, making the water basic.
At high pH, the concentration of H+ is very small. For example, at pH 11, the concentration of
H+ is 10-11 or 0.00000000001 mol/L. The concentration of OH-, however, is correspondingly
higher. The concentration of OH- can be expressed as follows:
(concentration of OH- in mol/L) = 10pH-14
At pH 11, the concentration of OH- is 1011-14 (10-3) or 0.001 mol/L, which is the same as the
concentration of H+ at pH 3.
The pH scale: the power of hydrogen
The pH scale is a logarithmic scale where a difference of one pH unit represents a power of ten
difference in the concentration of H+. For example, the concentration of H+ at pH 5 is ten times
higher than at pH 6, 100 times higher than at pH 7, and 1000 times higher than at pH 8.
Because each pH unit represents a power of ten difference in the H+ concentration, the pH
value represents the “power of hydrogen”. In fact, pH is most often defined as the negative
logarithm of the H+ concentration:
pH = -log10 [H+ concentration]
The same general pattern applies to OH-. The concentration of OH- at pH 8 is ten times higher
than at pH 7, 100 times higher than at pH 6.
3. How Can You Actually Determine
the pH of a Solution?
pH is a measure of the acidity or basicity of a solution. It is a logarithmic scale with a range from
0 to 14, where 7 is neutral. Solutions with a pH less than 7 are considered acidic, and those with
a pH greater than 7 are considered basic (alkaline). It is important to note that pH can have a
significant impact on the behavior of chemical reactions and biological systems.
In chemistry, pH is a numeric scale used to specify the acidity or basicity of an aqueous
solution. It is approximately the negative of the logarithm to base 10 of the molar concentration,
measured in units of moles per liter, of hydrogen ions. More precisely it is the negative of the
logarithm to base 10 of the activity of the hydrogen ion.
Solutions with a pH less than 7 are acidic and solutions with a pH greater than 7 are basic. Pure
water is neutral, being neither an acid nor a base. Contrary to popular belief, the pH value can
be less than 0 or greater than 14 for very strong acids and bases respectively.
Lemon juice tastes sour because it contains 5% to 6% citric acid and has a pH of 2.2. (high
acidity)
The effective strength of an acid or base in solution, or acidity, will vary with both the intrinsic
strength of the acid or base itself and the amount of the acid or base which is present in the
aqueous solution.
This is the chart of various solutions and their pH values.
The qualitative ranking of solutions as "more acidic" or "more basic" is possible on an empirical
basis of qualitative tests, but such an approach is not useful for quantitative discussion.
Quantitatively, the acidity of a solution is measured by and is equal to the concentration of
hydronium ion in that solution.
The pH of a liquid or solution is often an important piece of information in science. Measuring
pH can be done simply and quickly using pH test paper, pH indicator sticks, or a pH meter.
pH test paper and indicator sticks are pieces of paper or stiffer sticks that contain pH indicators
(chemicals that change color depending on how acidic or basic a solution is). To measure pH, a
piece of pH test paper or an indicator stick is dipped into the liquid. The color of the dipped
paper/stick is then matched to a color key that comes with the container of pH test paper or
indicator sticks. Each color on the key represents a different pH. An example of a used pH
indicator stick and the corresponding color key is shown below in Figure 1. pH meters are
electronic devices that used to measure pH. They consist of a probe that is dipped in a solution,
and a digital readout. pH meters are even more precise than pH test paper or indicator sticks.
Table 2 below discusses what types of pH measuring devices are best for different science
project applications, and offers a quick link to purchasing different pH test papers and indicator
sticks.
Chart showing the variation of color of universal indicator paper with pH
To determine the pH of a solution, you can use several methods. Here are some commonly
used techniques:
1. pH Indicator Paper: pH indicator paper, also known as litmus paper, is a simple and
inexpensive method to determine the pH of a solution. The paper is impregnated with a
mixture of pH-sensitive compounds that change color in response to different pH levels.
You dip the paper into the solution and compare the resulting color with a provided color
chart to determine the pH.
2. pH Test Strips: Similar to pH indicator paper, pH test strips are small strips of paper or
plastic with multiple indicator dyes. You immerse the strip in the solution and observe the
color change. Then, you compare the colors on the strip with a color chart provided by
the manufacturer to determine the pH.
3. pH Meter: A pH meter is a more accurate and precise instrument for measuring pH. It
consists of a pH electrode and a meter display. The pH electrode is a glass probe that
generates a voltage proportional to the hydrogen ion concentration in the solution. You
immerse the electrode in the solution and the pH meter displays the pH value directly.
4. pH Calculation: In some cases, you can calculate the pH of a solution if you know the
concentration of hydrogen ions (H+) or hydroxide ions (OH-) present. This method
requires knowledge of the dissociation constant of the specific acid or base involved and
the concentration of the solution.
It's important to note that pH measurements can be influenced by factors such as temperature,
contamination, and calibration of the instruments. Therefore, it's crucial to follow proper
procedures and ensure the accuracy of your measurement equipment.
How can you find the new pH of two solutions with different pHs?
Let us suppose that you are asked:
What is the pH of the final solution when you mix 50 mL of HCl solution with pH = 1.50 with 50
mL of HCl solution with pH = 4.50?
Calculate molarity of the HCl solution with pH = 1.50
If pH = 1.50
[H+] = 10^-1.5
[H+] = 0.0316 M
Calculate moles HCl in 50 mL solution
0.0316 mols / 1000 mL * 50 mL = 1.58*10^-3 mol HCl
Calculate molarity of the HCl solution with pH = 4.50
If pH = 4.50
[H+] = 10^-4.5
[H+] 3.16*10^-5 M
Calculate moles HCl in 50 mL solution
3.16*10^-5 mols / 1000 mL * 50 mL = 1.58*10^-6 mol HCl
Total mol HCl = 1.58*10^-3 mol + 1.58*10^-6 mol
Total mol HCl = 1.5816*10^-3 mol HCl in 100 mL solution
Molarity of HCl solution = 0.0158 M
[H+] = 0.0158 M
pH = - log 0.0158
pH = 1.80
4. Explain briefly the result of Hydration of Carbon Dioxide in Water
(add carbon dioxide and water).
When carbon dioxide reacts with water, carbonic acid is formed, from which hydrogen ions
dissociate, increasing the acidity of the system. Therefore, in addition to any greenhouse effect,
anthropogenic carbon dioxide emissions to the atmosphere can increase the acidity of the
atmosphere and precipitation. Around 30–40% of anthropogenic carbon dioxide emitted to the
atmosphere dissolves into the oceans, where the reaction with sea water has increased ocean
acidity by 0.1 pH units since pre-industrial times (Intergovernmental Panel on Climate Change,
Ocean ecosystems are affected both through acidification and by associated reductions in
carbonate ion concentrations, Around 20 per cent of anthropogenic carbon dioxide emissions to
the atmosphere are absorbed by the terrestrial biosphere, and the reaction between the
absorbed carbon dioxide and soil moisture can alter soil acidity. Carbon dioxide emissions to
the atmosphere can therefore increase the acidity of land, sea and air.
Simple answer is Carbon dioxide reacts with water to form Carbonic acid which is weak and
dissociates partly into bicarbonate ions. In terms of observable changes, the water gets weakly
acidic which although can be detected on a pH scale.
An interesting answer would be you can try it at home with just a pH indicator.
Blow air from your mouth in a vessel containing water and measure the changes in pH. You’ll
find the pH of water goes down as you keep blowing more and more air. There will come a time
when the pH becomes constant and no amount of blowing can change that. This is the point we
call equilibrium in chemistry.
One promising solution to reduce CO2 emissions is carbon capture and storage. There are a
number of options for long-term storage, of which saline aquifers have the largest capacity and
may therefore have the most potential. Saline aquifers are very large deep porous geological
formations saturated with brine, and are often rich in different metals. Although the initial
principal trapping mechanism is often an impermeable cap rock above the underground
reservoir (‘structural trapping’), solubility trapping and mineral trapping are also important in the
longer term. Solubility trapping occurs when carbon dioxide dissolves into the brine solution,
and mineral trapping occurs when the dissolved carbon dioxide reacts with the water to
eventually form stable carbonate compounds such as calcium carbonate and magnesium
carbonate. Long-term storage may also include the generation of stable carbonate compounds
in an industrial process above ground, or the injection of carbon dioxide into the deep oceans.
Which product is formed when carbon dioxide and water react in the same ratio?
The answer is Carbonic acid.
When CO2 reached with H2O in 1:1 ratio it forms H2CO3. The equation is as follows:
CO2 + H2O —-> H2CO3
Coca-Cola, Mountain Dew, Pepsi, etc.
That’s what carbonated drinks are, CO2 bubbled through a mixture of flavor syrup and water.
Carbonic acid is produced and that is why these drinks are acidic. Some practical trivia, Coke or
Pepsi will clean your car’s battery terminals and remove the limescale from your toilet bowl with
its acidic effects, if you are ever in a pinch for a cleaner.
Carbonic acid is the base for all fizzy drinks. So literally we have all drunk a mineral acid.
We see that the equation is balanced as also your query.
When carbon dioxide reacts with water, carbonic acid is formed, from which hydrogen ions
dissociate, increasing the acidity of the system.
Therefore, in addition to any greenhouse effect, anthropogenic carbon dioxide emissions to the
atmosphere can increase the acidity of the atmosphere and precipitation.
carbon dioxide, CO2 (aq), reacts with water forming carbonic acid, H2CO3(aq).
5. What is a weak acid?
A weak acid is an acid that only partially ionizes or dissociates in water to release hydrogen ions
(H+). This means that in a solution of a weak acid, there is a dynamic equilibrium between the
undissociated acid molecules and the dissociated ions. The concentration of hydrogen ions
produced by a weak acid is relatively low compared to a strong acid.
Weak acids have a lower tendency to donate hydrogen ions compared to strong acids. This is
due to their incomplete dissociation, where only a fraction of the acid molecules dissociates into
ions. The equilibrium expression for the dissociation of a weak acid can be represented as
follows:
HA ⇌ H+ + A-
In this equation, HA represents the undissociated acid, and H+ and A- represent the hydrogen
and conjugate base ions, respectively.
Examples of weak acids include acetic acid (CH3COOH), carbonic acid (H2CO3), formic acid
(HCOOH), and citric acid (C6H8O7).
It's worth noting that the terms "weak" and "strong" refer to the degree of ionization of an acid
and not its chemical properties or acid strength in terms of corrosiveness or reactivity.
bonds are stronger, near the proton that could be donated. That usually happens when its
radical or the rest of the atoms of the molecule are electron decliners, which means that they
“throw” the electrons in the proton’s area.
The proton is positive so a much bigger negative density around it will trap it inside the
molecule. Strong acids are the opposite. They radicals absorb the electrons, so the proton is
free to go.
Weaker acids are less reactive while the strong ones are more reactive. a weak acid or a weak
base is an acid or base that dissociates partially in water into its ions
Weak acids will dissociate partially to produce H+ ions.
pH values will be around 5 to 7.
All organic acids are weak acids.
Ex: CH2COOH: ethanoic or acetic acid
NH4OH: ammonium hydroxide (base).
6. What is a buffer? What is its importance in our body
system?
A buffer is a solution that helps maintain the pH of a system by resisting changes in its acidity or
alkalinity. It consists of a weak acid and its conjugate base (or a weak base and its conjugate
acid) that can react with added acids or bases without significantly changing the pH. Buffers
play a crucial role in our body systems to maintain the pH within a narrow and specific range, as
many biochemical processes are sensitive to changes in acidity.
Importance of Buffers in the Body:
1. pH Regulation: Various biological processes in our body, such as enzyme activity,
cellular functions, and metabolic reactions, are highly sensitive to changes in pH. Buffers
help maintain the pH of bodily fluids, including blood, saliva, and intracellular fluid, within
the optimal range. For example, the bicarbonate buffer system helps regulate the pH of
blood.
2. Acid-Base Balance: Buffer systems in our body play a vital role in maintaining the acidbase balance, which is essential for normal physiological functioning. They prevent large
fluctuations in pH that could be harmful to cells and tissues. The body's primary buffer
systems include the bicarbonate buffer system, phosphate buffer system, and protein
buffer system.
3. Respiratory and Renal Regulation: The respiratory and renal systems work in
conjunction with buffer systems to regulate the pH of the body. The respiratory system
controls the elimination of carbon dioxide (an acid) through breathing, while the kidneys
regulate the excretion and reabsorption of ions and molecules to maintain acid-base
balance.
4. Protection of Cellular Function: Maintaining a stable pH is crucial for the proper
functioning of enzymes, which are essential for various biochemical reactions in cells.
Enzymes have optimal pH ranges at which they work most efficiently. Buffers help
maintain the pH in these optimal ranges, ensuring proper enzyme function and cellular
activities.
Overall, buffers are essential in our body systems to maintain the pH homeostasis necessary for
normal physiological processes, enzymatic activity, and cellular function. They provide stability
and prevent detrimental effects that can arise from drastic pH changes.
1. Buffer Systems in the Body:

Bicarbonate Buffer System: This is one of the most important buffer systems in the body.
It involves the equilibrium between carbon dioxide (CO2), carbonic acid (H2CO3),
bicarbonate ions (HCO3-), and hydrogen ions (H+). This system helps regulate the pH of
the blood and extracellular fluid.

Phosphate Buffer System: This system involves the equilibrium between dihydrogen
phosphate ions (H2PO4-), monohydrogen phosphate ions (HPO42-), and hydrogen ions
(H+). It helps regulate the pH of intracellular fluids and urine.

Protein Buffer System: Proteins, especially those with ionizable amino acids, can act as
buffers. They can accept or donate hydrogen ions to maintain pH balance in both
intracellular and extracellular environments.
2. Acidosis and Alkalosis:

Acidosis: Acidosis occurs when the body's pH drops below the normal range (7.35-7.45),
making the body more acidic. This can lead to various health issues, such as impaired
organ function, nervous system disturbances, and metabolic problems.

Alkalosis: Alkalosis, on the other hand, happens when the body's pH rises above the
normal range, making the 1body more alkaline. Alkalosis can also cause adverse
effects, including muscle weakness, tetany, and respiratory difficulties.
3. Respiratory and Renal Compensation:

When there is an imbalance in pH, the respiratory and renal systems work together to
compensate and restore the proper pH level.

Respiratory Compensation: The respiratory system can alter the rate and depth of
breathing to adjust the levels of carbon dioxide (an acid) in the blood. For example,
when there is an increase in acid (lower pH), the respiratory system increases the
elimination of carbon dioxide through faster and deeper breathing.

Renal Compensation: The kidneys play a crucial role in regulating the levels of
bicarbonate ions (HCO3-) and hydrogen ions (H+) in the blood. They can reabsorb or
excrete these ions to help restore the proper pH balance.
4. Acid-Base Disorders:

Acid-Base disorders occur when there is a significant imbalance in the body's pH.
Examples include metabolic acidosis, respiratory acidosis, metabolic alkalosis, and
respiratory alkalosis. These disorders can be caused by various factors, including
respiratory problems, kidney dysfunction, metabolic imbalances, and certain diseases.

Maintaining the proper pH balance is essential for the normal functioning of our body.
Buffers, along with respiratory and renal mechanisms, work together to keep the pH
within the required range, enabling the optimal functioning of enzymes, cells, organs,
and physiological processes.
Example of buffer solution in our body is: human blood is a buffer solution.
Human blood contains a buffer of carbonic acid (H2CO3) and bicarbonate anion (HCO3-) in
order to maintain blood pH between 7.35 and 7.45, as a value higher than 7.8 or lower than 6.8
can lead to death. In this buffer, hydronium and bicarbonate anion are in equilibrium with
carbonic acid. Furthermore, the carbonic acid in the first equilibrium can decompose into CO2
gas and water, resulting in a second equilibrium system between carbonic acid and water.
Because CO2 is an important component of the blood buffer, its regulation in the body, as well
as that of O2, is extremely important. The effect of this can be important when the human body
is subjected to strenuous conditions.
In the body, there exists another equilibrium between hydronium and oxygen which involves the
binding ability of hemoglobin. An increase in hydronium causes this equilibrium to shift towards
the oxygen side, thus releasing oxygen from hemoglobin molecules into the surrounding
tissues/cells. This system continues during exercise, providing continuous oxygen to working
tissues.
the blood buffer is:
H3O++HCO−3⇌H2CO3+H2O
H3OHCO3H2CO3H2O
With the following simultaneous equilibrium:
H2CO3⇌H2O+CO2
Maintaining a constant blood pH is critical for the proper functioning of our body. The buffer that
maintains the pH of human blood involves a carbonic acid and bicarbonate ion.
When any acidic substance enters the bloodstream, the bicarbonate ions neutralize the
hydronium ions forming carbonic acid and water. Carbonic acid is already a component of the
buffering system of blood. Thus, hydronium ions are removed, preventing the pH of blood from
becoming acidic.
Chemical reaction diagram of bicarbonate ions neutralizing hydronium ions forming carbonic
acid and water
On the other hand, when a basic substance enters the bloodstream, carbonic acid reacts with
the hydroxide ions producing bicarbonate ions and water. Bicarbonate ions are already a
component of the buffer. In this manner, the hydroxide ions are removed from blood, preventing
the pH of blood from becoming basic.
If our blood pH goes to anything below 6.8 or above 7.8, cells of the body can stop functioning
and the person can die. This is how important the optimum pH of blood is!
Enzymes are very specific in nature, and function optimally at the right temperature and the right
pH; if the pH of blood goes out of range, the enzymes stop working and sometimes enzymes
can even get permanently denatured, thus disabling their catalytic activity. This in turn affects a
lot of biological processes in the human body, leading to various diseases.
Carbonate-bicarbonate buffer is the one that maintains pH in blood in the test tube it will be the
weakest but then most effective.
Human blood contains a buffer of carbonic acid (H2CO3) and bicarbonate anion (HCO 3-) in
order to maintain blood pH between 7.35 and 7.45, as a value higher than 7.8 or lower than 6.8
can lead to death. In this buffer, hydronium and bicarbonate anion are in equilibrium with
carbonic acid.
Carbonic acid (H2CO3) is a weak acid (pKa1=6.3, pKa2=10.3), and is formed when carbon
dioxide combines with water in a reaction catalyzed by the enzyme carbonic anhydrase. In
solution, carbonic acid is present in equilibrium with the bicarbonate ion via a simple proton
transfer reaction. For instance, a process that acidifies blood will be neutralized by the
bicarbonate ions thus minimizing the change in pH. A process that alkalizes blood will be
neutralized by the equilibrium concentration of carbonic acid.