Normality Problems and Examples PDF

Normality Problems and Examples Normality is a measure of concentration that is used in chemistry. It is defined as the number of equivalents of a solute per liter of solution. An equivalent is the amount of a substance that can react with or replace one mole of hydrogen ions (H+). This presentation...

Normality Problems and Examples Normality is a measure of concentration that is used in chemistry. It is defined as the number of equivalents of a solute per liter of solution. An equivalent is the amount of a substance that can react with or replace one mole of hydrogen ions (H+). This presentation will explore normality problems and examples, including various types of titrations and their applications. by Mona Elsayh Normality Calculation Examples 1 Example 1 In the reaction H3AsO4 + 2NaOH → Na2HAsO4 + 2H2O calculate and find the normality when it is 1.0 M H3PO4 N = Molarity (M) × Number of equivalents N = 1.0 × 2 Therefore, the normality of the solution = 2.0 Normality Calculation Examples 1 Example 2 Calculate the normality of the solution obtained by dissolving 0.321 g of the salt sodium carbonate (Na2CO3) in 250 mL water. (Assuming the salt solution is being used in a complete neutralisation by a strong acid.) (molecular weight =106 g/mol) Na2CO3 + 2H+(from acid) → H2CO3 + 2Na+ Normality= No. of equivalents/Volume(in Litre) Number of equivalent = weight/equivalent weight equivalents weight = molecular weight / n = 106/2=53 Number of equivalent = weight/equivalent weight =0.321/53=0.006 Hence, normality = No. of equivalents/ V (in litre) = 0.006/0.25 = 0.024 N Normality Calculation Examples 1 Example 3 What will the concentration and P-function of citric acid be if 25.00 ml of the citric acid solution is titrated with 28.12 mL of 5.4 x 10-4 M KOH? N=M.n N2= 5.4 x 10-4 *1= 5.4 x 10-4 N1 × V1 = N2 × V2 N1 × (25.00 mL) = (5.4 x 10-4 N) (28.12 mL) Therefore, the concentration of citric acid = 6.079× 10-4 N p-function =????? Normality Calculation Examples 1 Example 4 Calculate the normality of acid if 21.18 mL is used to titrate 0.1 g in 100 ml Na2CO3 (M.wt=105.99) Na₂CO₃ + 2H⁺ → 2Na⁺ + H₂O + CO₂ Equivalent wt= molecular weight /n = 105.99/2=52.995 Equivalents of Na2​CO3​=weight /Equivalent wt=0.1 /52.995​≈0.001887equiv Normality of acid=Equivalents of Na2​CO3​/Volume of acid in liters Volume of acid = 21.18 /1000=0.02118L Normality of acid=0.001887 /0.02118​≈0.089N Normality Calculation Examples 1 Example 5 What volume of 0.2 N Hcl is needed to completely neutralize 25 g of CaCO3​(Molecular weight = 100.09) CaCO3​+2HCl→CaCl2​+H2​O+CO2​. N=0.2 Wt=25 g M.wt= 100.09 N =M.n M= 0.1= V=2.49 L Normality Calculation Examples 1 Example 6 Calculate the normality of a solution contains 5% H2SO4. (M.wt=98) Molarity =g% *10 /M.wt =5*10/98=0.51 M N=M.N =0.51*2=1.02 N Normality Calculation Examples 1 Example 7 ​H2CO3 is a dibasic acid whose solution has a normality of 0.05 N. Calculate the concentration H2CO3 of in ppm M.wt=62 M = = 0.025 M M= 0.025 = Wt =1.55 g 1 ppm =1 mg/L Wt in ppm =1.55*1000=1550 mg/L Normality Calculation Examples 1 Example 8 ​A solution contains 8% H₃BO₃ (tribasic acid)Using the following information: The molecular weight is 61.83 Determine: 1.The concentration of H₃BO₃ in ppm. 2.The normality of the solution. 3.The weight of H₃BO₃ ​in a 250 mL sample of this solution. ​ 1- ppm 8 in 100 ml X in 1000 ml X=80 g/L to ppm 80*1000 =80000 mg/L 2- M =g% *10 /M.wt M=8*10/ 61.83=1.29 N=M.n =1.29*3=3.88 N 3- 80 in 1000 ml x in 250 ml wt in 250 ml =20 g Titration Applications Titration is a technique used to determine the concentration of a solution by reacting it with a solution of known concentration. This technique is widely used in various fields, including chemistry, biology, and medicine. 1 2 3 Acid-Base Titration Redox Titration Precipitation Titration This type of titration involves the This type of titration involves the This type of titration involves the reaction of an acid with a base. It reaction of an oxidizing agent reaction of two solutions to form is used to determine the with a reducing agent. It is used a precipitate. It is used to concentration of an acid or a to determine the concentration determine the concentration of a base. of an oxidizing or reducing substance that forms a agent. precipitate. Acid-Base Titration Acid-base titrations are a common type of titration used to determine the concentration of an acid or a base. The process involves the neutralization reaction between an acid and a base, where the endpoint is indicated by a color change of an indicator or a pH meter reading. Strong Acid-Strong Base Weak Acid-Strong Base Weak Base-Strong Acid The titration curve is smooth and The titration curve is irregular, with The titration curve is irregular, with steep near the equivalence point, a pH greater than 7.00 at the a pH less than 7.00 at the with a pH of 7.00 at the equivalence point. equivalence point. equivalence point. Titration Curves Titration curves are graphical representations of the pH of a solution as a function of the volume of titrant added. They provide valuable information about the strength of the acid and base involved in the titration. Strong Acid-Strong Base Smooth and steep curve, pH 7.00 at equivalence point Weak Acid-Strong Base Irregular curve, pH greater than 7.00 at equivalence point Weak Base-Strong Acid Irregular curve, pH less than 7.00 at equivalence point Polyprotic Acids Polyprotic acids are acids that can donate more than one proton (H+). The titration curve for a polyprotic acid will have multiple equivalence points, corresponding to the different stages of proton donation. Step 1 The first equivalence point corresponds to the neutralization of the first proton. Step 2 The second equivalence point corresponds to the neutralization of the second proton. Step 3 Additional equivalence points may exist for acids with more than two protons. Titration Applications in Various Fields Titration is a versatile technique with numerous applications in various fields. Its ability to determine the concentration of solutions makes it an essential tool for research, quality control, and analysis. Chemistry Biology Titration is used to determine Titration is used to measure the concentration of acids, the concentration of proteins, bases, and other substances. enzymes, and other biological molecules. Medicine Titration is used to determine the concentration of drugs and other substances in the body. Conclusion Normality is a crucial concept in chemistry, particularly in the context of titrations. Understanding normality calculations and the various types of titrations is essential for accurate and reliable chemical analysis. Titration techniques have wide-ranging applications in various fields, contributing significantly to scientific advancements and technological innovations.