Analytical Chemistry I - Lecture 1 - Dr. Yasmine Sharaf 2024-2025 PDF

# Pharmaceutical Analytical Chemistry I (PA 101) ## Zagazig National University Faculty of Pharmacy Pharm D Clinical Program **Dr/ Yasmine Sharaf** Ass. Prof of Analytical Chemistry Analytical Chemistry Department Faculty of Pharmacy Zagazig University Tel: 01066816943 Email: yaibrahim@pha...

# Pharmaceutical Analytical Chemistry I (PA 101) ## Zagazig National University Faculty of Pharmacy Pharm D Clinical Program **Dr/ Yasmine Sharaf** Ass. Prof of Analytical Chemistry Analytical Chemistry Department Faculty of Pharmacy Zagazig University Tel: 01066816943 Email: [email protected] ## 1-Overall Aims of the Course: On completion of the course, students will be able to outline theoretical bases and applications of acid-base, preciptimetric, complexometric and gravimetric reactions. ## Assessment | Assessment method | Marks | Percentage | |---|---|---| | Midterm exam | 10 | 10% | | Activity | 5 | 5% | | Practical practice & exam | 25 | 25% | | Oral exam | 10 | 10% | | Final written exam | 50 | 50% | | TOTAL | 100 | 100% | ## Assessment schedule | Assessment | Week | |---|---| | Assessment (1): Midterm exam | 7 | | Assessment (2): activity | 11 | | Assessment (3): Practical exams | 13 | | Assessment (4): Final written exam | 15 | | Assessment (5): Oral exams | 15 | ## What is Chemistry? - Chemistry = the study of matter and the transformation it undergoes - EVERYTHING is a CHEMICAL - Table salt = sodium chloride, NaCl - Table sugar = sucrose, $C_{12}H_{22}O_{11}$ - Clothes: Wool, Cotton, Polyester - Body: lipids, Proteins, Carbohydrates, DNA/RNA - You name it- it's a chemical! ## The Main Branches of Chemistry - Organic Chemistry - Inorganic Chemistry - Physical Chemistry - Biochemistry - Analytical Chemistry ## What is analytical Chemistry? - Analytical Chemistry is the branch of chemistry that deals with the analysis of different substances. - Analytical chemistry involves: - Separation - Identification - Quantification ## Types of Questions Asked in Analytical Chemistry - A) What is in the sample? (qualitative analysis) --- (Identity) - B) How much is in the sample? (quantitative analysis) --- (amount) ## Why is analytical chemistry important???? ### Application of Analytical Chemistry - Medical diagnosis e.g. measure of serum cholesterol, urine ketones, disease markers and blood glucose level. - Forensic survey e.g. analysis related to criminology such as DNA finger printing and poison analysis in blood samples. - Soil testing e.g check the minerals and nutrients necessary for plant growth and pesticide residues concentrations. - Food industry e.g. check food contaminants and preservative concentration in food samples. - Pharmaceutical industry e.g. determination of shelf lives of many medicines, check for the presence of adulterants in drugs, check for drug impurities, concentration of active constituents in formulation. ## Analytical chemistry is a central part of all scientific fields. ## Analytical Chemistry as the “Central Science” Medicine Toxicology Pharmacology Biochemistry BIOLOGY Botany Agriculture Ecology Analytical Chemistry Neurology Physiology Psychology Paleontology Geology PHYSICS Astronomy Meteorology Electronics Archaeology Metallurgy Engineering ## ANALYTICAL CHEMISTRY - **QUALITATIVE ANALYSIS** - **QUANTITATIVE ANALYSIS** - **CLASSICAL "WET" ANALYSIS** - **GRAVIMETRIC ANALYSIS** - **VOLUMETRIC ANALYSIS** - **INSTRUMENTAL ANALYSIS** - **OPTICAL METHODS** - **SEPARATION METHODS** - **ELECTRO-ANALYTICAL** **METHODS** ### 1. Classical Methods (Wet Analysis) - It is the analysis done generally in the liquid phase and not involve advanced instrumentation. - It is sometimes considered an old-fashion version of the chemical sciences. Nevertheless, it is very effective and widely used for several purposes. - It includes: - A. Volumetric Analysis - B. Gravimetric Analysis ### 2. Instrumental Analysis - It is the analysis using specific apparatus which perform measurements with the help of computers and software for processing and data analysis. - It depends on the physico-chemical, optical and electrical properties of the analytes e.g. spectrophotometric, potentiometric and conductometric methods of analysis. - These properties are measured which are quantitatively related to the concentration of the analyte. ### A. Volumetric Analysis - It depends on measuring the volume of a solution containing sufficient reagent to react completely with the analyte. - It is commonly used to determine the unknown concentration of a known reactant. - Volumetric analysis is often referred to as titration which is a laboratory technique in which one substance of known concentration and volume is used to react with another substance of unknown concentration. ### B. Gravimetric Analysis - It depends on measuring (weighing) the mass of the final product of reaction after its isolation in pure and stable from of definite chemical structure. ## Classification of volumetric analysis according to type of reaction involved - **Titration** - **Acid-base Titration** - **Redox Titration** - **Precipitation Titration** - **Complexometric Titration** ### A. Neutralization reactions: Acid (H+) + Base (OH¯)→ H2O+ Salt. ### B. Precipitation reactions: Hg (NO3)2 + 2NaCl → HgCl₂ (ppt) + 2 NaNO3 ### C. Complexation reactions: Ag+ + 2 CN → [Ag (CN)2] (Complex) ### D. Redox reactions: Ce4+ + Fe2+ → Fe3+ + Ce3+ ## Units of Concentration ### 1- Molarity, M - The gram molecular weight of substance in 1 Litre of solution - One Molar = mass of 1 mole (Molecular weight) dissolved in 1 liter of solution - 1 M NaOH prepared by dissolving 40 grams of NaOH in 1 liter of water ### 2- Normality, N = - It is gram equivalent weight of solute/liter of solution - Equivalent weight = Molecular weight / Valence - Equivalent weight of acid = Molecular weight / No. of replaceable H+ - e.g. Eq. wt of HCl= m.wt /1 and Eq. wt of H2SO4= m.wt/2 - Equivalent weight of base = Molecular weight / No. of replaceable OH- - e.g. Eq. wt of NaOH = m.wt / 1 and Eq. wt of Ba(OH)2 = m.wt/2 - Equivalent weight of salt = Molecular weight / (No. of Cation x its charge) - e.g. Eq. wt of NaCl = m.wt / 1 and Eq. wt of BaCl2 = m.wt/2 | Acid/base | K | M.W. | E.W. | |---|---|---|---| | HCI | 1 | 36.5 | 36.5 | | H2SO4 | 2 | 98.1 | 49.0 | | CaCO3 | 2 | 100 | 50.0 | | Al(OH)3 | 3 | 78.0 | 26.0 | ## Chapter 1 ## Acid base Titration in Aqueous Medium (Neutralization Titration) ## Acids & Bases - They are everywhere... - In your food - In your house - EVEN IN YOU!!!!! ## Arrhenius Definition of Acids - Acids dissociate to produce H+ ions to form hydronium ion_H3O+ in aqueous (water) solutions - HCI → H+(aq) + Cl (aq) ## Arrhenius Acids | Name | Formula | Acid Use | |---|---|---| | Hydrochloric acid | HCI | Stomach acid | | Nitric acid | ΗΝΟ3 | Used in fertilizers | | Sulfuric acid | H2SO4| Battery acid | | Phosphoric acid | H3PO4 | Food Flavoring | | Ethanoic acid | CH3COOH | Vinegar | | Carbonic acid | H2CO3 | Carbonated water | - Acids that contain one ionizable hydrogen--- monoprotic acids. - Acids that contain two ionizable hydrogens------- diprotic acids. - Acids that contain three ionizable hydrogens----triprotic acids. - Having more than one ionizable hydrogen does not mean stronger! ## Properties of an Acid - Tastes Sour - Conducts Electricity - Burning sensation if touched - Some acids react strongly with metals. - Turns blue litmus paper red ## Arrhenius Definition of Bases - Bases dissociate to produce OH- ions in aqueous (water) solutions. - NaOH → Na+ (aq) + OH-(aq) ## Some Common Bases | Name | Formula | Base Use | |---|---|---| | Potassium hydroxide | KOH | Called caustic potash Soap and batteries | | Sodium hydroxide | NaOH | Called caustic soda Soap, oven cleaner and paper | | Calcium hydroxide | Ca(OH)2 | Called caustic lime Leather making | | Magnesium hydroxide | Mg(OH)2 | Called milk of magnesia used as antacid Laxative | - The OH- ions interact strongly with certain substances, such as dirt and grease. ## Properties of Base - Slippery sensation if touched - Taste Bitter - Can conduct electricity. (Think alkaline batteries.) - Do not react with metals. - Turns red litmus paper blue. ## Arrhenius theory limitations - Concerning only aqueous solutions - Concerning only substances having hydrogen or hydroxide ions in their structure ## Brønsted-Lowry Theory The Brønsted-Lowry theory defines an acid as a hydrogen-ion donor, and a base as a hydrogen-ion acceptor. | HB | H+ + B- | |---|---| | HB is acting as an acid by donating a proton (H+), B is the conjugate base of the acid HB | B- + H+ → HB | | Acid | Conjugate Base | | HCI | Cl | | H2O | OH | | NH3 | NH4+ | | H2O | H3O+ | | Base | Conjugate acid | ## Brønsted-Lowry theory ### Conjugate Acids and Bases - A conjugate acid is the particle formed when a base gains a hydrogen ion. - A conjugate base is the particle that remains when an acid has donated a hydrogen ion. - NH3(aq) + H2O(l) → NH4+(aq) + OH-(aq) - Base - Acid - Conjugate - Conjugate - HCl(g) + H2O(l) → H3O+(aq) + Cl-(aq) - Acid - Base - Conjugate - Conjugate - Limitation: Substances like BF3, AlCl3 etc, do not have any hydrogen and hence cannot give a proton but are known to behave as acids. ## Lewis theory - Base is the substance that can donate a pair of electrons as it contains an atom with unshared electron pair (N, O, S, P). - ex., Amonia, Amine, ether, alcohol, ketone - Acid is the substance that can accept a pair of electrons. - ex., Aluminum trichloride (AlCl3), Ferric bromide (FeBr3), Boron Trichloride - The advantage of this theory is that many reactions can be considered acid-base reactions because they do not have to occur in solution. ## Acid-Base Definitions | Type | Acid | Base | |---|---|---| | Arrhenius | H+ producer | OH¯ producer | | Brønsted-Lowry | H+ donor | H+ acceptor | | Lewis | electron-pair acceptor | electron-pair donor | ## Salts - "Salts" are ionic compounds that are not acids or bases. - Metal cation (+) & nonmetal anion (-) | Acid, Base Name or Salt | | |---|---| | CaCl2 | calcium chloride | | Ba(OH)2 | barium hydroxide | | HCI | hydrochloric acid | | Na2SO4 | Sodium Sulphate | ## Arrhenius theory of ionization or Dissociation - *Non-electrolytes* are compounds that do not ionize at all in solution. - Examples of Non-electrolytes: Alcohols and glucose (sugar) readily dissolves in water, but because it does not dissociate into ions in solution and do not conduct electricity. - *Electrolytes* when dissolved in water split into two types of electrically charged particles called ions. - Examples of electrolytes (acids, bases and salts) dissociate into oppositely charged ions on dissolution in water. - NaCl → Na+ +CI- - HCI → H+ +CI - NaOH → Na+ + OH- - Ions are free to move. So, When electric current is passed through an electrolytic solution, charges move towards their respective electrodes, i.e. cations towards anode and anions towards cathode. - The electrical conductivity of the electrolyte solution depends on the number of ions present in the solution. More concentrated = more conductive - *Strong electrolytes* such as HCl etc. ionize completely in water. So they are good conductors. - *Weak electrolytes* such as acetic acid (CH3COOH) ionize only slightly. So they are bad conductors. - N.B. Pure water is a bad conductor of electricity. But when acid like HCl, a base such as KOH or a salt like Na2SO4 is dissolved in water, its conductivity is greatly improved. ## Electrolyte When dissolved in water, allows for electrical conductivity, (electron flow). Produces ions when dissolved in water. Substances which were formed by ionic bonds. Acids, bases and salts ## Nonelectrolyte When dissolved in water, does not allow for electrical conductivity, (electron flow). Does not produce ions when dissolved in water. Substances which were form by covalent bonds. Sugar - Note: for an electrolyte to conduct electricity, it must be dissolved in water ## Types of Acids ### Strong Acids (Mineral acids) - These acids ionize (break into cations and anions) almost completely and conduct electricity well in solution. They follow the equation: - HA(aq) → H+(aq) + A(a (aq) - There are *no* HA molecules in solution. ### The most common strong acids: - Hydrochloric acid (HCI) - Hydrobromic acid (HBr) - Hydroiodic acid (HI) - Sulfuric acid (H2SO4) - Nitric acid (HNO3) - Chloric acid (HCIO3) - Perchloric acid (HCIO4) -(N.B. Acids of all halides except F are strong acids) ## Types of Acids ### Weak Acids - These acids not completely ionize in solution. They are the most common type of acids. They follow the equation: - HA(aq) → H+(aq) + A(a (aq) - Most HA molecules are undissociated. ## The most common Weak Acids - Formic acid (HCOOH) - Carboxylic acids, which have the general formula RCOOH - (eg., Acetic acid CH3COOH) - Boric acid (H3BO4) - Carbonic acid (H₂CO₃) - Hydrofluoric acid (HF) ## Types of Bases ### Strong Bases (Alkali) - these bases completely ionize in solution - B + HOH(aq) →BH+(aq) + OH (aq) ### The most common strong bases: - Sodium hydroxide (NaOH): caustic soda - Potassium hydroxide (KOH): caustic potash - Others: LiOH, Mg(OH) 2, Ca(OH)2, Sr(OH)2, Ba(OH)2 ### Weak Bases (Alkali) - These bases not completely ionize in solution - ammonia (NH3) - amines ## QUIZ: MCQ - The compound HNO3 can be described as an - (1) Arrhenius acid and an electrolyte - (2) Arrhenius acid and a nonelectrolyte - (3) Arrhenius base and an electrolyte - (4) Arrhenius base and a nonelectrolyte - A substance that conducts an electrical current when dissolved in water is called - (1) a catalyst - (2) a non-electrolyte - (3) a metalloid - (4) an electrolyte - Which compound is an Arrhenius acid? - (1) CaO - (2) Κ₂O - (3) HCI - (4) NH3 - When one compound dissolves in water, the only positive ion produced in the solution is H3O+(aq). This compound is classified as - (1) a salt - (2) a hydrocarbon - (3) an Arrhenius acid - (4) an Arrhenius base - Which substance is an Arrhenius acid? - (1) Ba(OH)2 - (2) H3PO4 - (3) CH3COOCH3 - (4) NaCl - Which compound releases hydroxide ions in an aqueous solution? - (1) CH3COOH - (2) HCI - (3) CH3OH - (4) КОН - An Arrhenius base yields which ion as the only negative ion in an aqueous solution? - (1) hydride ion - (2) hydronium ion - (3) hydrogen ion - (4) hydroxide ion - The compound NaOH(s) dissolves in water to yield - (1) hydroxide ions as the only negative ions - (2) hydroxide ions as the only positive ions - (3) hydronium ions as the only negative ions - (4) hydronium ions as the only positive ions - How are HNO3(aq) and CH3COOH(aq) similar? - (1) They are Arrhenius acids and they turn blue litmus red. - (2) They are Arrhenius acids and they turn red litmus blue. - (3) They are Arrhenius bases and they turn blue litmus red. - (4) They are Arrhenius bases and they turn red litmus blue. - Which of the following is NOT a characteristic of acids? - 1. taste sour - 2. are electrolytes - 3. feel slippery - 4. react with metals - Which compound is most likely to act as an Arrhenius acid? - 1. H2O - 2. NH3. - 3. NaOH. - 4. H2SO4. - A Lewis acid is any substance that can accept - 1. a hydronium ion. - 2. a proton. - 3. hydrogen. - 4. a pair of electrons. - Identify each as a characteristic of an A) acid or B) base - 1. Sour taste - 2. Produces OH- in aqueous solutions - 3. Slippery touch - 4. Is an electrolyte - 5. Produces H+ in aqueous solutions - Identify each as a characteristic of an A) acid or B) base - 1. Sour taste - 2. Produces OH- in aqueous solutions - 3. Chalky taste - 4. Do not react with metals