Volumetric Analysis Bank Of Questions From St. Maximillian Secondary School (Tabata Segerea), Dated July 2022:
Volumetric Analysis Bank of Questions – Chemistry 1
Question 01
a) Mention the suitable indicators that can be used in the following titrations:
i) Hydrochloric acid with sodium hydroxide
ii) Sulphuric acid with sodium carbonate
iii) Ethanoic acid with sodium hydroxide
b) 14g of an impure sample of potassium hydroxide was dissolved in water to make 100ml of solution was then titrated with 1.25M nitric acid solution. 40ml of acid solution was required to neutralize 25ml of the alkali solution. Calculate the percentage purity of potassium hydroxide sample.
Question 02
a) A sample of mass 28.6g of hydrated sodium carbonate (Na_2 CO_3⋅10H_2 O) was heated such that its water was entirely absorbed by 32g of anhydrous copper (II) sulphate to form a blue compound of hydrated (CuSO_4⋅XH_2 O). Find the value of X in the copper sulphate.
b) Hydrated sodium carbonate (Na_2 CO_3⋅YH_2 O) solution was made by dissolving 178g of its crystals to make a litre of solution. 20〖” cm” 〗^3of the solution was found to neutralize 25〖” cm” 〗^3of a molar solution of nitric acid solution. Show all procedures to find the value of Y in the formula of hydrated carbonate.
c) Name the indicator you would choose for the following titration:
i. Hydrochloric acid versus ammonia solution
ii. Acetic acid versus sodium hydroxide
Question 03
a) 24〖” cm” 〗^3of a solution of 0.1M KOH were exactly neutralized by 30〖” cm” 〗^3of solution of sulphuric acid, calculate the concentration of acid in:
i) 〖”mol/dm” 〗^3
ii) 〖”g/dm” 〗^3
b) 25〖” cm” 〗^3of X_2 CO_3contains 10.6〖” g dm” 〗^(-3)required 23.00〖” cm” 〗^3and 0.217M of HCl for complete neutralization. Calculate:
i) The molarity of X_2 CO_3solution
ii) The molar mass of X_2 CO_3
iii) The atomic mass of X
iv) Name of element X
Question 04
a) 3g of impure Na_2 CO_3were made up to 250〖” cm” 〗^3of solution; 25〖” cm” 〗^3of this solution required 21.0〖” cm” 〗^3of 0.105M HCl for complete neutralization.
i) Write down the balanced equation for the reaction
ii) Calculate the molarity of pure Na_2 CO_3
iii) Calculate concentration of pure Na_2 CO_3
iv) Calculate % purity of Na_2 CO_3
v) Calculate % impurity of Na_2 CO_3
b) To what volume must 300〖” cm” 〗^3of 6.0M NaOH be diluted to give a 0.40M solution?
Question 05
a) Determine the number of molecules of water of crystallization in the sample (Na_2 CO_3⋅XH_2 O). If R.M.M is 286″ g/mol” .
b) 1.5g of an acid HX was dissolved in water and its solution made to 250〖” cm” 〗^3. If 30.2〖” cm” 〗^3of this acid solution neutralized 25〖” cm” 〗^3of 0.115M KOH, calculate:
i. Molarity of HX
ii. Molecular weight of HX
iii. Name of radical X
Question 06
a) Calculate the concentration of the following solutions:
i) 4.0g of sodium hydroxide (NaOH) in 250〖” cm” 〗^3of the solution
ii) 6.5g of potassium permanganate dissolved in water to make 100〖” cm” 〗^3solution.
b) 11.6g of X(OH)_2dissolved into water to make 500〖” cm” 〗^3of 0.4M XOH solution. Calculate:
i) Molar mass of X(OH)_2
ii) Atomic mass of X
iii) Identify element X
Question 07
a) 1.825g of XCl dissolved into water to make 500〖” cm” 〗^3of 0.1M XCl solution. Calculate:
i) Molar mass of XCl
ii) Atomic mass of X
iii) Identify element X
b) 4.9g of X_2 SO_4dissolved into water to make 250〖” cm” 〗^3of 0.2M X_2 SO_4solution. Calculate:
i) Molar mass of X_2 SO_4
ii) Atomic mass of X
iii) Identify element X
Question 08
a) 8.5g of hydrated sodium carbonate Na_2 CO_3was placed in the evaporating dish and heated to 100^∘ “C” . The final weight of anhydrous Sodium carbonate was 3.15g. Find number of moles of water of crystallization (“Na”=23,”O”=16,”C”=12,”H”=1).
b) 9g of hydrated oxalic acid H_2 C_2 O_4⋅nH_2 Owas placed in the evaporating dish and heated to 100^∘ “C” . The final weight of anhydrous oxalic acid was 6.413g. Find number of molecules of crystallization.
Question 09
a) 2.86g of hydrated Na_2 CO_3⋅nH_2 Owas dissolved into water to make 1.0 litre of 0.01″M ” Na_2 CO_3⋅nH_2 O. Calculate the value of n.
b) In an experiment to find the value of X in the compound MgBr_2⋅XH_2 O, 7.3g of the compound on heating to constant mass gave 4.6g of the anhydrous salt MgBr_2. Find the value of X (“R.A.M”:”Mg”=24,”Br”=80,”O”=16,”H”=1).
Question 10
a) 0.465g of a hydrated form of sodium carbonate exactly reacts with 75〖” cm” 〗^3of 0.10M hydrochloric acid. Calculate the number of molecules of water of crystallization present in one mole of the hydrated salt.
b) 0.970g of hydrated copper (II) salt CuX_2was heated to give 0.538g of the anhydrous salt. What is X?
Question 11
a) What mass of potassium hydroxide that is 85.9% pure is needed to prepare 1 litre of a 0.25M solution of potassium hydroxide? (The molar mass of potassium hydroxide is 56.11″ g/mol” ).
b) What volume of hydrochloric acid that is 37.1% pure and has a density of 1.2〖” g/cm” 〗^3is needed to prepare 1 litre of 0.1M of hydrochloric acid solution? (The molar mass of hydrochloric acid is 36.5″ g/mol” ).
Question 12
a) Find the molarity of sample H_2 SO_4containing 98% purity by weight H_2 SO_4and having impure density of 1.63〖” g/cm” 〗^3(“H”=1,”S”=32,”O”=16).
b) 12.5〖” cm” 〗^3of 0.5M H_2 SO_4neutralized 50〖” cm” 〗^3of NaOH solution. Calculate:
i) Molarity of the base
ii) Concentration in 〖”g/dm” 〗^3
Question 13
a) 5.3g of sodium carbonate (Na_2 CO_3) dissolved into water to make 250〖” cm” 〗^3solution. 10〖” cm” 〗^3of this solution was required to complete neutralization of 25〖” cm” 〗^3of HCl acid. Calculate the molarity of the acid (“Na”=23,”C”=12,”O”=16).
b) 5.1g of impure sodium carbonate solution was dissolved in water to make 500〖” cm” 〗^3of solution. 20〖” cm” 〗^3of this solution was titrated against 20.45〖” cm” 〗^3of 0.04M hydrochloric acid. Calculate the percentage purity of the sodium carbonate solid.
Question 14
a) 20〖” cm” 〗^3of solution containing 7〖” g/dm” 〗^3XOH neutralized by 25〖” cm” 〗^3of 0.1M HCl. Calculate:
i) Concentration of base in 〖”mol/dm” 〗^3
ii) Molar mass of XOH
iii) Atomic mass of X and identify X
b) 20〖” cm” 〗^3of KOH were titrated against HNO_3acid contain 3.0g in 200〖” cm” 〗^3solution. The base solution was made by dissolving 52g of impure in water to make 1.0 litre of solution. The volume of acid used was 24.4〖” cm” 〗^3.
i) Find molarity of base
ii) Find the percentage purity
Question 15
a) 28.6g of hydrated Na_2 CO_3dissolved into water to make 1 litre. 23〖” cm” 〗^3of this solution require 15.33〖” cm” 〗^3of 0.3M HCl solution to complete neutralization.
i) Molarity of base
ii) Value of X
b) Prepare 600〖” cm” 〗^3of 0.4M nitric acid from stock solution. Calculate: Given: “RMM”=63, “Density”=1.42〖” g/cm” 〗^3, “Percentage purity (assay)”=68%
i) Concentration of the nitric acid in the manufacturer’s bottle?
ii) Calculate the molar concentration of the dilute solution of the nitric acid you have prepared.
Question 16
a) The commercial sample of sulphuric acid containing 96% w/w H_2 SO_4and having density of 1.82〖” g/cm” 〗^3:
i) Calculate the molarity of commercial sample of sulphuric acid
ii) What will be the molarity of a solution obtained by adding 10〖” cm” 〗^3of the commercial acid in (i) above in water to make 15 litres of solution?
b) You are provided with the following:
Solution SS containing 1.825 g of HCl per 〖”dm” 〗^3of the solution.
Solution YY containing 0.5 g of XOH in 250〖” cm” 〗^3of the solution.
Methyl orange indicator MO
Procedure: Put solution SS in the burette. Pipette 20〖” cm” 〗^3or 25〖” cm” 〗^3of solution YY into a titration flask. Add two drops of MO indicator. Titrate solution YY against solution SS from the burette until a colour change is observed. Repeat the procedure to obtain three more readings.
i) Record your results in a table below.
ii) …〖” cm” 〗^3of solution YY required …〖” cm” 〗^3of solution SS for complete neutralization.
iii) The colour change at the end point was from …to …
iv) Write a balanced chemical equation for the reaction between solution YY and SS
v) Calculate the:
a. Molarity of SS
b. Molarity of YY
c. Molar mass of XOH
d. Atomic mass of X in XOH
Question 17
You are provided with the following:
Solution X, containing 1.575 g of pure hydrated oxalic (H_2 C_2 O_4) acid in 250〖” cm” 〗^3of the solution.
Solution Y containing 2.8 g of potassium hydroxide per 1000〖” cm” 〗^3of the solution.
Phenolphthalein indicator (P.O.P)
Procedure: Put solution X in the burette, pipette 25〖” cm” 〗^3of solution into titration flask. Titrate solution X from burette against Y in the titration flask until the colour change is observed. Note the burette reading, repeat the procedure to obtain three more readings and record your results in a table.
i) …〖” cm” 〗^3of solution X required …〖” cm” 〗^3of solution Y for complete reaction
ii) The colour change at the end point was from …to …
iii) Determine the concentration of solution Y in 〖”mol dm” 〗^(-3)and in 〖”g dm” 〗^(-3).
iv) Determine the molar mass of hydrated oxalic acid
v) Calculate the value of “a” and percentage of water of crystallization in the H_2 C_2 O_4⋅aH_2 O
Question 18
a) Exactly 21.5〖” cm” 〗^3of hydrochloric acid required 25〖” cm” 〗^3of sodium carbonate solution for complete neutralization. The alkali was prepared by dissolving 5g of the pure base in 0.377 litres of solution. Calculate the concentration of the acid in grams per litre.
b) Explain how you can prepare 2.0〖” dm” 〗^3of 0.05M sodium solution from a stock solution of 12M sodium hydroxide solution that is 90% pure. What is the mass of sodium hydroxide in your final solution?
Question 19
a) Exactly 0.35g of divalent metal carbonate, TCO_3, were dissolved completely in 100〖” cm” 〗^3of 0.1M HCl solution. The excess acid required 20〖” cm” 〗^3of 0.15M NaOH solution for complete neutralization. Find the relative atomic molecular mass of the metal carbonate. What is identity of metal T?
+ 3
b) 48g of a metal carbonate (Y_2 CO_3) were dissolved to make 200〖” cm” 〗^3of solution. The solution was titrated with 1M sulphuric acid. 20〖” cm” 〗^3of the solution reacted completely with 37.5〖” cm” 〗^3of sulphuric acid. Determine the number of moles of sulphuric acid used in the reaction.
+ 3
Question 20
a) The number of moles of the metal carbonate in 2〖” cm” 〗^3of the metal carbonate solution. The R.A.M of the metal in the metal carbonate (Y is not actual symbol of the metal). 5.25〖” cm” 〗^3of 2M nitric acid reacted completely with 20〖” cm” 〗^3of a solution containing 56.25 g of sodium carbonate in 250〖” cm” 〗^3of solution. Determine the percentage purity of sodium carbonate.
+ 3
b) In an experiment to find the value of X in the compound MgBr_2⋅XH_2 O, 7.3g of the compound on heating to constant mass gave 4.6g of the anhydrous salt MgBr_2. Find the value of X (“R.A.M”:”Mg”=24,”Br”=80,”O”=16,”H”=1).
Question 21
a) About 0.106g of a divalent metal carbonate XCO_3were dissolved completely in 25〖” cm” 〗^3of a 0.125M HCl solution. The resulting solution was neutralized by 20〖” cm” 〗^3of 0.05M NaOH solution. Find the relative atomic mass of metal X.
b) 25〖” cm” 〗^3of sodium hydroxide solution was titrated with 0.1M hydrochloric acid with recorded titration results. Determine the molar concentration of the sodium hydroxide solution.
Question 22
a) What do you understand by Volumetric analysis?
b) A volume of 30〖” cm” 〗^3of sulphuric acid with a concentration of 0.2M was mixed with a volume of 20〖” cm” 〗^3of barium chloride solution with concentration of 0.31M.
i) Find out which substance was in excess.
ii) Calculate the amount in grams of the precipitate formed in this reaction.
Question 23
a) Define the following terms:
i) Molar solution
ii) Standard solution
b) 8.48g of sodium carbonate crystal were made up to 250〖” cm” 〗^3of solution. 25〖” cm” 〗^3of this neutralized 30〖” cm” 〗^3of 0.2M of hydrochloric acid. Calculate the number of molecules of water of crystallization in sodium crystals.
c) A solution of concentrated nitric acid contain 80% by weight of HNO_3. If the density of acid is 1.5〖” g/cm” 〗^3, calculate:
i) The molarity of acid
ii) The volume of concentrated acid that will be required to make 0.7〖” dm” 〗^3of 0.4M aqueous nitric acid
Question 24
a) Write the suitable indicator in each of the following acid-base reactions:
i) Acetic acid and sodium hydroxide
ii) Nitric acid and ammonium hydroxide
iii) Potassium hydroxide and sulphuric acid
b) 70〖” cm” 〗^3of X_2 CO_3solution required 50〖” cm” 〗^3of 0.2M HCl for complete neutralization.
i) Write a balanced chemical equation for the reaction.
ii) Calculate the concentration of X_2 CO_3in: “a. ” 〖”mol/dm” 〗^3, “b. ” 〖”g/dm” 〗^3.
iii) If the compound X_2 CO_3has a molar mass equal to 106″ g/mol” , calculate the relative atomic mass of X.
Question 25
a) Exactly 21.5〖” cm” 〗^3of hydrochloric acid required 25〖” cm” 〗^3of sodium carbonate solution for complete neutralization. The alkali was prepared by dissolving 5g of pure base in 0.337 litres of solution. Calculate the concentration of acid in Molar per 〖”dm” 〗^3and grams per 〖”dm” 〗^3.
b) Define the following terms:
i) Concentration
ii) Molarity
c) What is the concentration of solution containing 26.5g of anhydrous sodium carbonate in 5〖” dm” 〗^3of solution in 〖”Mol/dm” 〗^3and in 〖”g/dm” 〗^3?
Question 26
a) Mwl. Dowile prepared two solutions for chemistry students:
Solution G containing 36.5g of hydrochloric acid in 1 litre solution.
Solution B containing 2.65g of M_2 CO_3per 0.5〖” dm” 〗^3of solution.
During an experiment students extracted 10〖” cm” 〗^3of G and diluted it to 100〖” cm” 〗^3mark, filling it in a burette for titration with solution B (25〖” cm” 〗^3).
i) Copy the table and fill the blanks.
ii) Calculate the average volume that neutralized the base.
iii) Assume that sulphuric acid of the same molarity was used in the place of hydrochloric acid, would it be different in the titre volume used? Give reason.
iv) Write a balanced chemical equation between B and G and the corresponding ionic equation with state symbols.
v) Showing your procedures clearly, calculate the molar mass of M_2 CO_3and hence identify element M.
b) Solution Q was made by dissolving 3.45g of a D_2 CO_3in water and diluting it to 250〖” cm” 〗^3. 25〖” cm” 〗^3of solution Q required 20〖” cm” 〗^3of 0.25 molar HCl solution. Calculate:
i) Molarity of Q
ii) Molar mass of Q
iii) Determine the relative atomic mass of D in D_2 CO_3and name the element D
Question 27
a) 8.50g of a sample of iron required just 75〖” cm” 〗^3of 3.0M HCl to dissolve it and give a neutral solution. Calculate the percentage purity of the sample of iron.
b) 25〖” cm” 〗^3of a solution containing 0.196g of metal hydroxide YOH were neutralized by 25〖” cm” 〗^3of 0.1M hydrochloric acid solution. Calculate:
i) The molarity of the hydroxide solution
ii) The molar mass of YOH
iii) Identify the element Y
Question 28
a) A sodium carbonate solution was made by dissolving 179g of its crystals to make a litre of solution. 20〖” cm” 〗^3of the solution was found to neutralize 25〖” cm” 〗^3of a molar solution of nitric acid. Calculate:
i) Concentration of base in 〖”mol/dm” 〗^3and 〖”g/dm” 〗^3
ii) The number of molecules of water of crystallization in Na_2 CO_3⋅XH_2 O
b) A mass of 14.3g of hydrated sodium carbonate solution (Na_2 CO_3⋅XH_2 O) was dissolved in water and diluted to make 250〖” cm” 〗^3of solution. Then 25〖” cm” 〗^3of the solution was titrated with 0.5M hydrochloric acid. The volume of acid used was 20〖” cm” 〗^3. Determine the number of molecule of water of crystallization “X” in (Na_2 CO_3⋅XH_2 O).
+ 3
c) What volume of 18.4M sulphuric acid is required to prepare 200〖” cm” 〗^3of 0.5M of sulphuric acid?
Question 29
a) Give the meaning of the following terms:
i) Indicator
ii) Titration
iii) Solution
b) 17.25g of Metal carbonate (X_2 CO_3) was dissolved in water to make 250〖” cm” 〗^3of solution. 20〖” cm” 〗^3of this solution was then titrated with 0.8M hydrochloric acid.
i) Copy and complete the table provided.
ii) Calculate the average volume of the acid used.
iii) Write a balanced chemical equation for the reaction which took place in the above experiment.
iv) Determine the atomic mass of metal in the metal carbonate above.
Question 30
a) Hydrated sodium carbonate (Na_2 CO_3⋅YH_2 O) solution was made by dissolving 178g of its crystals to make a litre of solution. 20〖” cm” 〗^3of solution was found to neutralize 25〖” cm” 〗^3of a molar solution of nitric acid solution. Show all procedures to find the value of Y in the formula of hydrated carbonate.
b) Give the applications of neutralization in daily life.
c) What volume of nitric acid that is 68% pure and has a density 1.42〖” g/cm” 〗^3is needed to prepare 600〖” cm” 〗^3of 0.4M of nitric acid solution? (Given molar mass of nitric acid = 63″ g/mol” ).
Question 31
a) A sample of mass 28.6g of hydrated sodium carbonate (Na_2 CO_3⋅10H_2 O) was heated such that its water was entirely absorbed by 32g of anhydrous copper (II) sulphate to form a blue compound of hydrated (CuSO_4⋅XH_2 O). Find the value of X in the copper sulphate.
b) 25〖” cm” 〗^3of 0.1M HCl were neutralized by 23〖” cm” 〗^3of sodium hydroxide solution. Calculate the concentration of alkali in grams per litre.
Question 32
a) 25〖” cm” 〗^3of molar solution of sodium hydroxide is diluted to 85〖” cm” 〗^3. Calculate concentration of solution after dilution (Give your answer in two decimal places).
b) An unknown mass of anhydrous sodium carbonate was dissolved in water and the solution made up to 250〖” cm” 〗^3. 25〖” cm” 〗^3of this solution neutralized 20〖” cm” 〗^3of 0.25M nitric acid. Calculate the unknown mass of sodium carbonate.
Question 33
a) 12.3g of MgSO_4was thermally decomposed gently, 6.0g of MgSO_4remained. Show all procedures systematically to write the formula of identified water of crystallization.
b) 25〖” cm” 〗^3of 0.1M HCl was enough to dissolve completely 3.35g of hydrated sodium carbonate (Na_2 CO_3⋅XH_2 O) which is dissolved in 250mls of distilled water whereby only 25〖” cm” 〗^3needed for reaction. Determine number of water of crystallization in sodium carbonate.
Question 34
a) In one titration experiment 25〖” cm” 〗^3of hydrated sodium carbonate Na_2 CO_3were titrated against 20〖” cm” 〗^3of 0.25M hydrochloric acid. The solution of sodium carbonate was made by dissolving 7.15g of the compound in 250〖” cm” 〗^3of distilled water.
i) Write down a balanced equation to represent the acid-base reaction.
ii) Find a molarity of hydrated sodium carbonate.
iii) Calculate the value of X in the hydrated sodium carbonate.
b) What is the molarity of a solution containing 10% by mass of calcium hydroxide in 0.5〖” dm” 〗^3of solution?
Question 35
a) A Maximilian student prepared a solution by dissolving 2.65g of anhydrous sodium carbonate in water to make one litre solution. 25〖” cm” 〗^3of this solution reacted with 23〖” cm” 〗^3of a monobasic acid of formula HT containing 1.984g of acid per litre of solution. Show clearly your calculations in details to find the relative atomic mass of the element T.
b) What volume of water should be added to 10M NaCl solution to prepare 3.5 litres of a 0.2M NaCl solution?
Question 36
a) A mass of 14.3g of a hydrated sodium carbonate solution (Na_2 CO_3⋅XH_2 O) was dissolved in water and the solution diluted to make 250〖” cm” 〗^3of solution. Then 25〖” cm” 〗^3of this solution was titrated with 25.18〖” cm” 〗^3of 0.5M of hydrochloric acid. Determine the number of molecules X of water of crystallization in the hydrated carbonate.
b) A form three student conducted titration which involved solution NaXCO_3and Nitric acid solution. If 25〖” cm” 〗^3of solution of NaXCO_3required 12.5〖” cm” 〗^3of 0.2M of nitric acid for complete neutralization, calculate:
i) The molarity and molar mass of NaXCO_3if its concentration in 〖”g/dm” 〗^3is 8.4.
ii) The atomic mass of element X given that NaXCO_3reacted with HNO_3in a 1:1 mole ratio.
iii) Suggest the name of element X
iv) Give the name of Anion XCO_3
v) Assign the correct charge of anion XCO_3
Question 37
a) Exactly 15.8〖” cm” 〗^3of 0.3M HCl solution were enough to neutralize 23〖” cm” 〗^3of sodium carbonate solution prepared by dissolving 29.46g of the hydrated sodium carbonate (Na_2 CO_3⋅XH_2 O) in a litre of solution. Find the value of X which is the number of molecules of water of crystallization.
b) 51.75g of metal carbonate (Y_2 CO_3) were dissolved to make 200〖” cm” 〗^3of solution. The solution was titrated with 1M of sulphuric acid, 20〖” cm” 〗^3of the solution reacted completely with 37.5〖” cm” 〗^3of sulphuric acid. Determine:
i) The number of moles of sulphuric acid used in the titration.
ii) The number of moles in 20〖” cm” 〗^3of the metal carbonate solution.
iii) The R.A.M of the metal in metal carbonate.
iv) The element “Y”.
v) Write its electronic configuration.
Question 38
a) 14g of impure KOH was dissolved in water to make 100〖” cm” 〗^3of solution. The solution was then titrated with 1.26M of Nitric acid solution. 40〖” cm” 〗^3of the acid required 25〖” cm” 〗^3of alkali solution to be neutralized.
i) Work out the percentage purity and impurity of KOH sample.
ii) Which solution seem to be more concentrated for that neutralization reaction? State reason.
b) Exactly 0.35 grams of divalent metal carbonate MCO_3were dissolved completely in 100〖” cm” 〗^3of 0.1M HCl solution. The excess acid required 20〖” cm” 〗^3of 0.15M NaOH solution for complete neutralization. Find the relative molecular mass of the metal carbonate and Identify metal M.
Question 39
a) 12g of the mixture of sodium carbonate and sodium sulphate were dissolved in water to make up to 500〖” cm” 〗^3. 25〖” cm” 〗^3of the solution required 25〖” cm” 〗^3of 0.2M sulphuric acid for complete neutralization.
a. Which substance in the mixture reacted with sulphuric acid?
b. Write a correct balanced chemical equation took place in the reaction above.
c. Calculate the number of moles of sulphuric acid reacted with the mixture.
d. Determine the molarity of the substance reacted in mixture.
e. What was the mass of the substance which reacted in the mixture?.
f. What was the percentage of sodium sulphate in the mixture?
b) A solution of HCl contains 3.6g of the Acid in 1〖” dm” 〗^3of solution. 20〖” cm” 〗^3of this solution is neutralized by sodium carbonate in which 1.1g of it dissolved to make 100〖” cm” 〗^3of solution. Calculate:
i) Mole ratio for the reaction
ii) The Molarities of acid and Carbonate of the solution
iii) The volume of the carbonate solution
Question 40
a) Give the meaning of the following terminologies:
i) Impure sample
ii) Pure sample
iii) Percentage purity of a substance
b) 14g of impure KOH was dissolved in water to make 100〖” cm” 〗^3of solution. The solution was then titrated with 1.26M of Nitric acid solution. 40〖” cm” 〗^3of the acid required 25〖” cm” 〗^3of alkali solution to be neutralized.
i) Work out the percentage purity and impurity of KOH sample.
ii) Which solution seem to be more concentrated for that neutralization reaction? State reason.
Question 41
a) Samples of sodium hydroxide solutions of unknown concentration were titrated against 0.2M of Ethanoic Acid (CH_3 COOH) and results were obtained with a pipette volume of 10〖” cm” 〗^3:
i) What is the average volume of the acid used?
ii) Calculate the molarity of NaOH and its concentration in 〖”g dm” 〗^3if the chemical equation is: NaOH_((aq) )+CH_3 COOH_((aq) )→CH_3 COONa_((aq) )+H_2 O_((l) )
iii) Name the suitable indicator for this reaction and state the reason.
iv) What are the conditions necessary for neutralization reaction above (at least three points)?
b) 51.75g of metal carbonate (Y_2 CO_3) were dissolved to make 200〖” cm” 〗^3of solution. The solution was titrated with 1M of sulphuric acid, 20〖” cm” 〗^3of the solution reacted completely with 37.5〖” cm” 〗^3of sulphuric acid. Determine:
i) The number of moles of sulphuric acid used in the titration.
ii) The number of moles in 20〖” cm” 〗^3of the metal carbonate solution.
iii) The R.A.M of the metal in metal carbonate.
iv) The element “Y”.
v) Write its electronic configuration.
