Question

(3) (4) B) Preparation a) Place about 50 ml of distilled water in a 0.1 liter volumetric flask. b) Use a 1 ml pipette to transfer 0.83 ml of conc. HCl to the flask. Add distilled water until the volume is 0.1 liter. Save for later use. Prepare 0.1 liter of 0.1 M sodium hydroxide (MW= 40.0 (skip this exercise)). A) Calculations B) Preparation Prepare 0.1 liter of 0.1 Macetic acid (MW = 60.1(check the bottle for FW)). A) Calculations (Concentrated acetic acid, usually called glacial acetic, has a density of 1.05 g/ml and is 99.7% pure) B) Preparation and save for later use Prepare a 0.1M acetate buffer (pH 5.0) from the 0.1 M acetic acid and 0.1 M sodium acetate A) Calculations a) Use the Henderson-Hasselbalch equation to determine the ratio of sodium acetate to acetic acid necessary to yield a pH of 5.0. (5) pH = pk + log conjugate basel/acid] 5 = 4.76 + log (acetate [acetic acid] 0.24 = log (acetate/acetic acid) (acetate/acetic acid) = 1.74 B) Preparation a) Use a graduated cylinder to measure 87 ml of 0.1 M sodium acetate and then add it to 50 ml of 0.1 M acetic acid h) Store the solution in a llask labeled I Macetate buffer (pH 5.0). Check pll

can you please write the calculations with clear writing and explanations and thank you

Answer 1

[Acetic acid] =0603649 m This concentration is after mixing. If we want to prepare total volume 100 ml of . acetate buffer nie. o.12, the mols of each component. ave, NA - 0.06351 xoolk ive. CHAT-Acid K 0.00635 I mols. iie, numbe of moles of nu: = aeid = 0.006351 mols. Le number of moles of salt is calculated as, NÄ = 0.03649 molxo.lt NA = 0.00 364gmol Hoe neem be od moles of salt is 0.00364-9 mols. If both having starting concentrations as olm volume of salt we can find volume they each start with, VA Csalt) – IL 0.00 Ool mols of an X 0.003649 VÁCsatt) = 0.003649x10' = 0.03649 L (Acetate) 1 litre = 1000ml 0.03649 litre ? AVÁ in ml = 0.03649x1000 = 36.49 m. Vacid Cacetic acid Ver acid) = - 0.1 mols of acetic acid X 0.066351 mols

: Volume of = 0.06351 L Acid AS I litre = 1000 un then 0.06351 litre = ? VAcid (Acetic acid) - 0.06351x 1000 Volume of acetic acid. = 63151 und Therefore o.lm of 63.51ml acetic acid required to prepare ocl litre of acetate better with onlm of 36.49 ml of acetate ie. sodium acetate

pH-pka & pH = pka + log of [conjugate base] Cacid] pH = 5 . (given) pka = 4-76. (standard). 5 = 4.76 + log [acetate] CAcetic acid] 5-4.76 = log [Acetate] Acetic acid) 0.24 = log (Acetate/ Dacetic acid Anti(0.24] = [Acetate] [Acelicaid? . 1-74 = [Acetate? [Acetic oeid? Now, it total concentration of buffer is o.lom then Cacetic acid ] + 1074 CHA] = 0.1m. where, 1-74 CHA) 174Cacetic acid) [Acetate). [Acetic acid] + 1-74 CAcetic acid) = 0.1m. : Acetic acid](1+1+4)=0m [Acetic acid] = = (1+1.74) - 2.74 Acetic acid = 0.0 36 4 3 2 . Chal.concentration of salt = 0.1-003649 - 006351 M.

③ Prepare ocl litre of old sodium hydroxide m.w. = 40.0 (4) Calculations - NaOH : Molecular weight of sodium hydroxide is 40.0 - - - - - (given). . . Molarity is defined as number of moes of solete dissolved in per litre of solution M(molarity) = n . I litre. where n-number of moles. = W i e number of moles - weight of NaoH for compano Molecular weight of Molarity of solution is givens au nim. NaOH (er compound). and volume of solution is given as o.12 we have to calculate weight of sodium hydroxide required to prepare a flitre of 0.1m sodium hydroxide. We can use the formula to calculate the weight of sodium hydroxide (NaOH) required to prepare the above solution. ool litre = 10om as-1 L=1000u formula Molarity = Weight & 1000 Molecular weight inmi). .. o.IM = Weight of NaOH & 1000 100m. 40.0 .: CIMX40.0X100 1000 = weight of NAOH

. 0. 1x40xtoo = Weight of NagH. 2006 10 • 1x 40 = 0.4 gmc Weight of NaOH Hence, weight of NaOH required to prepare oos litre of o. im Noon solution is 0.4gm. Preparation- Weight NaOH 0.4gm disolve it in sout of distilled water in beaker. Then by using wolumetric flask of 100ml dilute it upto the mark. This is the solution of o. IM NaOH with volume 0.1 litre 7 e 100ml. O Prepare a orm acetate buffer (pH=5.0) from the dim acetic acid and o.pm sodium acetate > Calculatims -- Griven : Concentration of giver acetic acid = olm O concentration of sodium acetate = 0.1 m from above soldions que have to prepare oom * acetate bretter Butter. A solution which resist to change in pt . after addition of acid or base is called as butles Hint-Criven) Handerson - Hasselbalch equation to determine the ratio of sodium acetate to acetic and necessary to yield a pH of 5.0