Question

What is the pH of a solution made by dissolving 4.8 g of K₂CO₃ and 6.6 g of KHCO₃ in 500. mL of water?

**ACID BASE TABLE** -> refer to table for values

Acid Name Conjugate Acid ka pka Conjy Conjugate Base Base Name perchloric acid HCIO4 >>1 perchlorate ion hydrohalic acid HX (X=1,Br, CI) halide ion sulfuric acid >>1 hydrogen sulfate ion nitric acid >>1 nitrate ion H2804 HNO3 || 1307+ To coa >>1 <0 x1- >> RO HS044- >> | NO3- 1.0 10.00 H20 10.17 10.77 1037 5.9 x 10-2 1.23 HC204 hydronium ion water iodic acid HIO3 0.17 0.77 iodate ion oxalic acid H2C204 hydrogen oxalate ion sulfurous acid H2SO3 1.5 x 10-2 1.82 hydrogen sulfite ion hydrogen sulfate ion HSO41- sulfate ion phosphoric acid H3PO4 dihydrogen phosphate ion hydrofluoric acid HF fluoride ion nitrous acid HNO2 nitrite ion lactic acid HC3H503 lactate ion || 1.2 x 10-2 1.92 so4² 7.5 x 10-3 12.12 H2PO4+ 7.2 x 10-4 3.14 F1- T4.0 x 104 3.40 No₂" 6.4 x 10-5 3.85 C3H5031- 1.8 x 10-4 3.74 CHO2?- 6.4 x 10-5 C2042 1.9 x 10-5 4.72 N31- 1.8 x 10-5 4.74 C2H302?- (4.3 x 10-7 ||6.37 |HCO39- formic acid HCHO2 formate ion hydrogen oxalate ion HC204" oxalate ion hydrazoic acid IHN3 azide ion acetic acid HC2H302 acetate ion carbonic acid H2CO3 hydrogen carbonate ion 1.0 x 10-7 7.00 sulfite ion hydrogen sulfide ion hydrogen sulfite ion HS031- hydrosulfuric acid H2S dihydrogen phosphate ion e ion | H2PO4?- hypochlorous acid HCIO 1.0 x 10-7 7.00 HS1- 6.2 x 10-8 7:21 HP042 3.5 x 10-8 7.46 Ciol- hydrogen phosphate ion hypochlorite ion ammonium ion NH1+ 5.6 x 10-10 9.25 NH3 ammonia hydrocyanic acid HCN cyanide ion hydrogen carbonate ion HCO31- carbonate ion hydrogen phosphate ion THPO₄2- 4.0 x 10-10 9.40 CN1- | 1.7x10-11 10:33 C032 4.8 x 10-13 12.32 ||P043- 11.3 x 10-13 | 12.89 s² 1.0 x 10-14 14.00 0-1- phosphate ion hydrogen sulfide ion HS 1- sulfide ion water H20 hydroxide ion ammonia NH3 <<10-14 amide ion INH₂1- 162- hydroxide ion T410-14 D OH1- oxide ion

Answer 1

I mol KCO₂= (2x39) + 12+ (3*16) = 1389 K2CO3 138 & 4.8 g K Coza 4.8 mol K₂CO3 ? 0.035 mol kzcoa 500 m2 water contain 0.035 mol KC e Concentration of K2CO₃ = 0.035 mall 3 200 x 103 mol/ 20.07(M) Again, 1 mol KHCO3 = (39+1+12+(3x16) = 100g 6.6 g of KHCO3 = GIE = 0.066 mol KHCO

Now, 0.066 mol KH CO₂ also present in 500 me solution - concentration of KHCO3 a 60cc molle ? 0.132 (M) Now, the acid KHCO3 and its conjugate bone K2CO₃ toromed a buffer solution which pka value given that 10.33, so, for a buffen solution: - The Handenson-Horssel baleh equation is – 0 P4, pka - (ее Ск, созу [KHCO3] a 10.33+ log (0.07 ) a 7.132) 210.33 -0.275 2 10.058 of the solution is 10.058 The pit