Question

EQUL 499- Det. Of pH of Strong Acid, weak acid, salt, and buffer solution Discussion Topics Discussion Topics (need to submit in Blackboard): 1. What is a buffer? • A buffer is a solution that, when introduced to a new environment, undergoes minimal pH change, typically when adding acidic or basic solutions. These are extremely important for life because the pH of human blood is delicate and even if it is changed by 0.1, there may be catastrophic effects. 2. What are the buffer components in part VI of your experiment? • In part VI of our experiment, the buffer components are 3. Compare the expected initial pH (calculated pH) of the buffer is the measured pH 4. How did the addition of NaOH change the pH of your buffer? 5. How did the addition of HCl change the pH of your buffer? 6. Is your buffer system more resistant to NaOH or HCI? Why do you think that is? 7. How do the buffers work? Give at least 2 examples of buffer systems that uses outside of the laboratory. D. Focus BD

Answer 1

Bubber component's ! First we know about the buffer solution. solution of single substance Buffer solutions are of two types Solutions of Mixtures (1) solution of single substances solutions of mixtures → Colution of the sait of weaQuid and — Ojcin too types weak base le weak acid + weak base. a) Acidic buffer misterett © Bastic ogoer eg CH2 COO NH3 ammonium autate f weak auid & salt of a mixture of week this week and with base + salt of this formed from Strong bose. eg. weak best with (NaOH + NH4) CH₃ COOH & CHI, COONa strong aud eig, its salt with NH4OH + NHALL autic and bost u its sett with Stroy acid such as Hu weak acid Stroy weokbos NA SH (436004 t Nook

NULUI + NOOM Dulu such as Hul aguona thyo fast-noel Components :- TV part ~ ie ito mede from which acid base pari as defining above; - 11 Nall - formed from strong acid and shoy bose as HU + Nãoho Nole 'ie its a buffer solution ( NA GYM30g or cff Coopa (sedium acetate) is a Acidic Buffer having components in CH, COOH + NOOH - CH, COONQ + H2O autic acid Strong 1 Aldic 1 bulley) when water Roos (H3COONa dissociate completely due to its valt CHE COONO ---- CH3COo + wat - Ú O Aud due to its week nature dissociate as (withegon/ enz.com = 460B + t 0 Due to common ion effect' ponization of acid (west) Coslom in cine en l a Subpressed. This in the solution, there are excess of the Loo in a small amount of at ion Qutford Aldi bubber bolo nature as

e When small amount of an aud ' added to the above mixture Solution, the H+ ion given by the acid combine away with the Che Woo® fons given by the aud to form oz COOH which is almost duesmot ionize as crizooo + HO - CH₂COOH - ang 1 from outside) Thus, the Ht ions concentration & hence the pH of the solution remains Olmost constanti Similarly when a small amount of a base is added, the Of ions given by the base combines with the Ht cons already present from to form Hao which is almost doesnot ionize as As the 4t ions are HT + oH - HO W Consumed, the em in from egn (9) from In both (B & W equ egn (1) shifts towards right side H@ @ OA neutralized ice. (acc. to de Chatelier as principe). Thus, more pH of solution remains the crycoon dissociate to make up of the at constant deu to buffer action. ions. Hence the Ht ion concentration or the pH of the solution doesnot charge. outside

But - dissociale we value of pH about 7 as ci similarly Sodium Cochonneue formed frorn; а Он + H,D, H Na HD, + H2O strony (weak acid) | ACC to definiation it must be - acidic buffer. sodium l il pH belowt Completely dissociate due to salt nature, bicarbona - Na Hoz Nat +Hoo as and give H₂ CO 3 + H2O 2 H 30t + Hog tweak base) weak aud * Hoz + H2O = 4got + cool (strong boce) hence gives pH about 7. because when cal react with water liberete of as cazul + HO = on + Hugo ise the pH of solution. Najoz; dissouate as, - Nad z taho QN0OH + H₂ 3 As Noor is strong base and H₂ O3 is weak and its br must above 7.

I NHAU , NHACO + H₂O 1 1. - NHGOH + HU week base strong aud hence pH below 7. (1) NHA CH₂O2 ; CCOONHA + HO CH₃ COOH + NHGOH weak Qu'd wecke bau salt neutral wecke au'd D CLONA; CM, 600 Na + Mgo - che coon + NUOM L week strong bout In o poje I am taking about A herca dell - basic. pH more than 7. combinations ie week acid + its valt with strony base. But in components we just need to know whether it goues story acid or bou. It and is story thin pu audic (le belowa) if string ů host then pH above of (8

1 (4) from alla gruen in the qu (3) Originel buffer solution pH = 1.84 - calculated = 1.84 from data given in the question when GM HCl is added in buffer solution calculated and measured values are some having values, (buffer col: + 6M HU) - 1.82 - le chey in pH is 1.84-1.82 = 0.02 is very smell charge. from my previous discussion of CH₂ COO Na (action of buffer); which is an acidic buffer, because in acl dic buffer when it from outside added maintain by the suppression in dissout weak acid and thar å a smell ation of change in pro (5) Asif it is acidic buffer, when Naomie Bose is added, eem of een S shifts towards right side more tt dissociate and combines with Naon make the pH constant acetic acid weak. as waoh ý a strong base and which neutralizes the SH at dome extent, ofter further addition by Primeasin

1 on increases the pr of solution Hence their ů a vast change in pH after addition of NaoH from given data, we get (6 m NaOH t buffer dol) = 24.41 change in pH = 8.46 - 1.84 = 0.57 Buffer solution maintains pH bleo 1.82-8-41 on add" HU and Nach (6) This buffer solution & more si resistant to Hu because when HUI added change in PH U 0.02 (very loss). But when Nach with equal amount and equal strength (wone) added change in pH is more ie 0.57. (+) Buffer action explained previously with the LOONa. Eg's - (In biological process t (0) H coś con act as the principle buffer in human blood as a 19 els

human blood as a in when acid enters the blood, the extra H3ot ions are removed by HOğ ions which is act as base, 1 4603 + H₂O4 - Hq O3 + H2O 1. Or Hož + H+ H2O + CO2 my when base penters the blood, extra of ions are removed by carbonic Qud , 1 H 0 3 taono coa tahao In industrial processes : Monosodium phosphate (MSP) is wealin textile manufacturing, where it acts as MSP Nara PO4 a low pH buffer for acid dyeing of textile fibers. Eco